Inbred lines of non-heading Chinese cabbage with different resistance to downy mildew were conducted for studying the metabolism of resistance to downy mildew As shown by the result  before the inoculation  the lignin contents in healthy leaves were positive correlated to the resistance to downy mildew of inbred lines of non-heading Chinese cabbage  while there was no obvious correlation between chitinase activities and the resistance to downy mildew of inbred lines