A recombinant inbred line (RIL) population, NJRIKY, which was derived from the cross Kefeng 1 xNannong 1138-2, was used to constructed the genetic linkage map. Larval weight and pupae weight of cotton worm [Prodenia litura (L.) Fabricius] were examined and used as indicators of resistance. Based on the linkage map constructed with SSR markers of this RIL population, one QTL responsible for larval weight was mapped on linkage group G20-O and the position was 31.91 cM. The QTL's additive effect was 0.0408 and explained 11.74 of the total variation of the larval weight. Two QTLs associated with pupae weight were mapped on linkage group G8-D1b+W and G17-L and the positions were 14.71 cM and 0.01 cM, respectively. The QTLs' additive effects were -0.0139 and 0.0103 ,which explained 11.30 and 6.36 of the total variation of larval weight, respectively.