The aim of this study was to investigate the optimal manganese level in the basal diet of female minks during the idophase. One hundred and fifty healthy female minks with the body weight of (1 005±113) g were selected and assigned into 5 groups by randomized block, there were 30 replicates in each group and 1 minks in each replicate. Supplemental levels of manganese in basal diets were 0 (group Ⅰ), 15 (group Ⅱ), 50 (group Ⅲ), 100 (group Ⅳ) and 500 mg/kg (group Ⅴ), respectively. Manganese was added as organic chelated form, and manganese content in the basal diet was about 25 mg/kg. The experimental period was from January 26, 2011 to June 23, 2011.The results showed that there were no significant differences in serum estradiol and progesterone contents, pregnancy days, mating rate, kidding rate, litter number, number of born alive, birth litter weight, number of weaned alive, weaning survival rate, and average individual weight of 1 and 7 days of age by supplemental level of organism chelated manganese (P>0.05), but kidding rate, litter number, number of born alive, number of weaned alive, weaning survival rate had an increase trend with increasing of manganese supplemental level. Supplemental level of organism chelated manganese had little effect on mating span, but could shorten average duration days of first mating and promote the concentration level of mating. There were significant differences in weaning weight of litter, average individual weight of 15 and 45 days of age, and average daily gain from 1 to 45 days of age (P<0.05). The weaning weight of litter tended to increase at first and then decrease with increasing of manganese supplemental level, and groups Ⅳ and Ⅴ were significantly higher than group Ⅱ(P<0.05); the average individual weight of 15 days of age had a decrease trend with increasing of manganese supplemental level, and significant differences were found between groups Ⅰ and Ⅱ and group Ⅴ (P<0.05); the average individual weight of 45 days of age and average daily gain from 1 to 45 days of age in group Ⅱ were the lowest, and had significant differences compared with group Ⅰ (P<0.05). Under this study conditions, based on comprehensive consideration of the reproduction performance of female minks and growth performance of young minks, it is suggested that optimal supplemental level of manganese by organic chelated form in the basal diet (about 25 mg/kg) is 100 mg/kg for female mink during the idophase, that is total level of manganese in the diet is about 125 mg/kg.