Objective:To investigate the effects of vitamin A on appetite and the gene expression of MC4R, POMC, and to explore the mechanism of vitamin A on rats’ appetite. Methods: Male Sprgue-Dawley (SD) rats were divided into two groups: group A (the vitamin A deficient group) and group B (the vitamin A normal control group). Seventy-four days later, 16 rats were selected from group A and then divided into two groups: group A1 (the vitamin A deficient group) and group A2 (the vitamin A administration group). Also 8 rats were selected from group B as group B1 (the vitamin A normal control group). At the 79th day, all the rats in the three groups were sacrificed, and some relevant indices were measured. The remaining rats in group A were divided into two groups again: group A3 (the vitamin A deficient group) and group A4 (the vitamin A supplement group). The remaining 8 rats in group B was group B2 (the vitamin A normal control group). All the rats were sacrificed after 30 days. Some relevant indices were also measured. Results: In the VAD group, the total food intake was significantly lower than that of the control group. After giving vitamin A supplement, the total food intake obviously increased. The expression of MC4R and POMC in the VAD group was increased, while POMC was decreased obviously after vitamin A supplement. Conclusion: Vitamin A affects the expression of related appetite regulator, resulting in the change of food in take.