This experiment used Apis mellifera L. as a research object to carry out indoor out-of-group adult worker bee feeding experiments by adding different levels of manganese to the adult worker bee diet. The lifespan, physiological and biochemical indexes and manganese related gene expression of the bees were measured, and strive to find the nutritional effects and mechanisms of manganese on bees. From the Apis mellifera L. sister bee colony, a total of 1 250 one-day-old work bees that had just emerged from the house were randomly divided into 5 groups with 5 replicates in each group and 50 bees per replicate. One group was control group, and bees in the control group were fed a syrup diet without manganese. The other four groups were experimental groups, and bees in the experimental group were fed the syrup diet supplemented with different levels of manganese gluconate, and the levels of manganese in the syrup diets were 50, 100, 150 and 200 mg/kg, respectively. Put 50 bees in each group into a special bee feeding device and placed them in a constant temperature and humidity incubator. Set the temperature in the incubator to 30℃ and the humidity of (50±5)%. Regularly used a syringe to fed 3 mL of syrup diet, each group was sampled at 7, 14 and 21 days of age, and the manganese-related enzyme activities and manganese-related gene expression levels in adult worker bee body were measured. Moreover, samples were taken at 21 days of age to determine the manganese content in adult worker bee body. From the Apis mellifera L. sister bee colony, another 1 250 one-day-old work bees that had just emerged from the house were grouped and fed according to the above treatment, observed bee performance, removed dead bee body, and fed until all death. The average lifespan of each group of bees was counted. The results of showed as follows:1) the average lifespan in the 50 and 100 mg/kg manganese addition groups was significantly longer than that in the 150 and 200 mg/kg manganese addition groups and the control group (P<0.05). 2) With the supplemental level of manganese in the diet increasing, the manganese content in adult worker bee body was significantly increased (P<0.05). 3) With the supplemental level of manganese in the diet increasing, the activity of manganese superoxide dismutase (MnSOD) in the 7- and 14-day-old adult worker bee body was firstly increased and then decreased. When the supplemental level of manganese was 150 mg/kg, the activity of MnSOD reached the highest value and significantly higher than that in the control group (P<0.05). The manganese catalase (MnCAT) activity in the 7- and 14-day-old adult worker bee body was firstly increased and then decreased. And the MnCAT activity in the 21-day-old adult worker bee body was increased. When the supplemental level of manganese was 150 mg/kg, the activity of MnCAT in the 14-day-old adult worker bee body reached the highest value and was significantly higher than that in the control group (P<0.05). The activity of arginase in the adult worker bee body at 7, 14 and 21 days of age was firstly increased and then decreased. 4) With the supplemental level of manganese in the diet increasing, the expression level of MnSOD gene in the adult worker bee body at 7, 14 and 21 days of age was firstly increased and then decreased. When the manganese supplemental level was 150 mg/kg, the expression level of MnSOD gene in the adult worker bee body at 7 and 14 days of age was significantly higher than that in the other groups (P<0.05). The expression levels of MnCAT gene in 14- and 21-day-old adult worker bee body was firstly increased and then decreased. When the manganese supplemental level was 100 mg/kg, the expression level of MnCAT gene in 14- and 21-day-old adult worker bee body was significantly higher than that in the control group (P<0.05). In addition, the expression level of arginase gene in 14-day-old adult worker bee body in 150 mg/kg manganese addition group was significantly higher than that in the control group and 200 mg/kg manganese addition group (P<0.05), and the expression level of arginase gene in 21-day-old adult worker bee body in 200 mg/kg manganese addition group was significantly higher than that in the control group and 50, 150 mg/kg manganese addition groups (P<0.05). The results indicate that supplementing an appropriate amount of manganese in the diet can prolong the lifespan, improve the antioxidant capacity, immunity and other physiological functions of adult worker bees for Apis mellifera L.