THE JOFFREY BALLET has often been ambitious.

But this fall, it is being audacious. The company is reviving ''Le Sacre du Printemps (The Rite of Spring)'' in its original form, as given in Paris by Sergei Diaghilev's Ballets Russes on May 29, 1913, at the Theatre des Champs-Elysees. The production, shown for the first time in Los Angeles on Sept. 30, will receive its New York premiere Wednesday evening at the City Center.

The opening bars of Igor Stravinsky's dissonant score must have convinced Parisians in 1913 that ''Sacre'' (as dancers call the ballet for short) would be extraordinary. Vaslav Nijinsky's choreography owed little to traditional balletic ideals of grace in its depiction of the ceremonies of a prehistoric Slavic tribe, among them a sacrificial ritual during which a maiden dances herself to death to appease the gods. Nicholas Roerich's designs looked barbaric, and the entire production seemed an assault on eye and ear. Catcalls arose. So did cheers. That opening night performance was, quite literally, a riot.

''Sacre'' made history. Roerich's vividly colored and patterned designs reflected the interest of many early 20th-century artists, including the Cubists, in primitive art. And both Stravinsky's rhythmically vital score and Nijinsky's unconventional choreography, with its sudden jumps and shudderings, were bold experiments.

Yet, the choreography almost slipped into oblivion. It was danced only eight times. Diaghilev and Nijinsky later quarreled, and when Nijinsky's career was cut short by mental illness, people assumed his ''Sacre'' was lost. Diaghilev offered a new ''Sacre'' in 1920, rechoreographed by Leonide Massine. Although such other choreographers as Maurice Bejart, Kenneth MacMillan, Paul Taylor, Martha Graham, Mary Wigman and Pina Bausch have also rechoreographed it, not until now has anyone tried to restore Nijinsky's version.

Three people became convinced that a restoration was possible. Robert Joffrey, director of the Joffrey Ballet, has long admired Nijinsky as a dancer and choreographer. His company's revival is being supervised by Millicent Hodson, an American dance historian, and her husband, Kenneth Archer, a British art historian. Ms. Hodson became interested in ''Sacre'' in the 1970's; the ballet was the subject of her doctoral dissertation at the University of California at Berkeley. In 1981, she met -and then married - Mr. Archer, an expert on Roerich.

To reconstruct the work, Ms. Hodson and Mr. Archer have tried to assemble and correlate every scrap of information that exists about the 1913 production. They have sifted through reviews and dancers' reminiscences, and they have studied photographs and artists' drawings. At times, they have been detectives. At other times, they have resembled archaeologists putting the fragments of an ancient artifact together.

Ms. Hodson, Mr. Archer and Mr. Joffrey each recently commented on what makes the ballet unusual. Ms. Hodson said Nijinsky's choreography is notable for its ''faceting and breaking up of movements. The movement is constantly broken into fractions. One figure may start a movement, then other people will take it up in slightly different ways. What could be called cells of movement are constantly forming and splitting.''

She pointed out that the choreography possesses ''a great sense of restriction. And from the restriction comes much of the ballet's power.'' Many sequences involve such seemingly simple activities as walking, running or jumping. But these motions are performed with the body held in such contorted poses that their execution is difficult. Mr. Joffrey commented, ''Nijinsky's movements are not just rearrangements of classical steps. Rather, he tried to invent movements that would be uniquely appropriate to 'Sacre' and to no other ballet.''

Two documents proved especially valuable to the choreographic reconstruction. One was a score in which Stravinsky had written descriptions of the stage action above the music. Although, according to Ms. Hodson, these notes seldom mention specific dance steps, they do indicate what happens by means of such phrases as ''The men group together'' and ''Here they fall to the floor.''

Even more crucial has been a score with choreographic notes by Marie Rambert, a Polish dancer who was an expert in a method of rhythmic analysis known as Dalcroze eurhythmics. Asked by Diaghilev to help Nijinsky analyze the complex music, deeply impressed by the choreography, she sought to note down as much of it as possible. Later, she founded London's Ballet Rambert, which remains a major British company. To raise money for her troupe in a financial crisis, she auctioned off her score during the 1960's. Its present whereabouts is unknown. However, almost as if she foresaw such a fate, she transcribed her notes into a second copy of the score. Unfortunately, she mislaid it, and it was only after her death in 1982 that the copy was found tucked away in a cupboard in her home.

Ms. Hodson had interviewed Rambert before her death. Ms. Hodson also started staging passages of choreography on dancers willing to be guinea pigs. But it was only after she had consulted the Rambert score that she felt certain that a complete reconstruction was feasible.