Abstract: To examine the effect of bovine colostrum powder on the reproductive development and reproductive ability of offspring rats when the exposure began in uteri, the two-generation reproduction study was designed.The hormone levels in serum, the development of reproductive organs and reproductive date were detected.There were no significant differences in fertility or reproductive organ development of both parents and offspring female pups, or in the germ cell numbers and the germ activity of both parents and offspring male pups between bovine colostrum powder group and control group (p>0.05) .There were no significant differences in the hormone levels of parents and offspring male pups between two groups (p>0.05) .However, the progesterone content of parents female rats and the prolactin contents of parents and offspring female pups in bovine colostrum powder group were significant lower than those of control group (p<0.05) .The anogenital distance of F2a female pups in bovine colostrum powder group was shorten (p<0.05) , and the vaginal open of F2b female pups in bovine colostrum powder group were delayed comparing with control group (p<0.05) .It was unknown whether they occurred by chance or was biologically significant until this treatment effect is replicated.