The genetic difference of 10 rice parents (5 CMS lines and 5 The genetic difference of 10 rice parents (5 CMS lines and 5 restorer lines) was analyzed by molecular markers of grain weight loci in rice. The correlation between genetic distance and grain weight and heterosis was studied by reference to the performance of 25 combinations. The results showed that the correlation between genetic distance of grain weight loci and control heterosis wassignificant(r=0.28*) ，correlation between genetic distance of grain weight loci and grain weight was significant(r=0.26*), and correlation between genetic distance of grain weight loci and female parent heterosis wasvery significantly correlated(r=0.41**). The study of molecular markers predict heterosis in hybrid rice.