Abstract: Seeds of rape (Brassica napus L.) were cultured in the presence of exogenous salicylic acid ranging from 0.08 to 10.00 μmol/L (0、 0.08、 0.40、 2.00 and 10.00 μmol/L)to see the effect of salicylic acid on the formation of lateral roots in rape. The results show that 0.40 μmol/L salicylic acid treatment enhanced the formation of lateral roots significantly, in which the number of lateral roots was increased by 47.8% compared with the control. More auxin and lower abscisic acid were detected both in leafs and roots of the treatment of 0.40 μmol/L salicylic acid. It showed that salicylic acid might be involved in the regulation of lateral root formation through influencing the content of endogenous auxin and abscisic acid in rape.