The aim of this study was to investigate the effect of four factors including goat milk powder, ascorbic acid, incubation temperature and inoculum size on ACE inhibitory peptides in fermented goat milk by Lactobacillus bulgaricus LB6. The concentration of goat milk powder was 10%, 12%, 14%, 16% and 18%, ascorbic acid was 0.01%, 0.03%, 0 05%, 0.07% and 0.09%, incubation temperature was 27℃, 32℃, 37℃, 42℃ and 47℃ and inoculum size was 3%, 4%, 5%, 6% and 7%, respectively. The results were as follows: The concentration of goat milk powder, ascorbic acid, incubation temperature and inoculum size had a significant effect on ACE inhibition and growth of Lactobacillus bulgaricus LB6 in fermented goat milk (p<0.05). The optimal concentrations of goat milk powder and ascorbic acid were 14% and 0.03% and the optimal temperature and inoculum size were 37℃ and 5% for ACE inhibition, corresponding ACE inhibitions were 74.02%, 89.64%, 74.98% and 74.32%, respectively, respectively.