Pen-hsi, also spelled Pen-ch’i, Pinyin Benxi, or Benqi , city in Liaoning sheng (province), China. It is situated some 45 miles (70 km) southeast of Shen-yang (Mukden) on the T’ai-tzu River.

From the time of the Liao dynasty (907–1125) it was the centre of a small-scale iron industry, and coal began to be mined in the late 18th century. The startling modern growth of Pen-hsi began with the establishment in 1905 of the Pen-hsi Coal Mining Company with joint Chinese and Japanese capital. In 1911 the company began iron smelting and changed its name to the Pen-hsi Coal and Iron Company. It was efficiently managed and remained important but gradually became dominated by Japanese interests.

After the establishment of the Japanese puppet state of Manchukuo (formerly Chinese Manchuria) in 1932 and the formulation of the Manchurian Industrial Development Plan in 1936, the Manchukuo government developed Pen-hsi’s iron and steel production. Much of the iron from Pen-hsi had low phosphorus and sulfur content and was in demand for the munitions industry. The city’s works also began to produce special steels for the Japanese navy.

In 1945–46 the occupying Soviet forces dismantled most of the equipment, but the plant was restored by 1950, and during the early 1950s much new equipment was installed by Soviet technicians. By 1957 Pen-hsi’s iron production had reached the World War II level, and new local sources of ore were being exploited. The iron industry is closely integrated with the large iron and steel complex at An-shan, to which much of Pen-hsi’s pig iron production is transported. Since 1958 the steel output of Pen-hsi has been greatly increased. Pen-hsi also has large cement, chemical, and nonferrous alloy manufacturing industries. It also has thermal power stations. It is connected by rail with Shen-yang, An-shan, and Lü-ta (Ta-lien). Pop. (1988 2003 est.) 725834,600176.