This experiment was conducted to study the effects of environmental temperature and vitamin A on testicular development and relative hormones of rearing drake (12～17 weeks) in cage. A 2×3 factorial arrangement of treatment was employed with 2 temperature levels (suitable indoor temperature (18±1) ℃ and lower indoor temperature (2±1) ℃) and 3 vitamin A levels (4 000, 10 000 and 15 000 IU/kg) .One hundred and forty-four drakes were randomly allotted into 6 groups and each group contained 6 replicates with 4 drakes. The results showed as follows: 1) environmental temperature significantly affected triiodothyronine (T3) and thyroxine (T4) (P＜0.01) but had not significant influenceon insulin (P>0.05). The T4 level was significantly affected by vitamin A levels (P＜0.01); however, T3 and insulin were not significantly affected by vitamin A levels (P>0.05). There was significant effect of interaction of environmental temperature and vitamin A levels on insulin level (P＜0.05); 2) follicle stimulating hormone (FSH) (P＜0.05), luteinzing hormone (LH) (P＜0.01) and testosterone (T) in serum (P＜0.01) were significantly influenced by environmental temperature. Vitamin A levels significantly affected LH level (P＜0.05), but had not significantly influenced on the level of FSH and T (P>0.05); 3） testicular relative weight and testicular relative length were significantly influenced by environmental temperature (P＜0.05), however, vitamin A levels did not influence testicular relative weight and testicular relative length (P>0.05). In conclusion, it would appear from the results of the present study that 15 000 IU/kg vitamin A could efficiently regulate the thyroid hormone levels which were influenced by lower indoor temperature, and make them closed to normal physiology standard; and the 10 000 IU/kg vitamin A could reduce the adverse effects of lower indoor temperature on testicular development of drakes.［Chinese Journal of Animal Nutrition, 2009，21(6）:829-833］