In order to understand the dietary habit of Apodemus agrarius which inhabited Dongting Lake area,stomach contents of 223 samples were observed under anatomical lens.Samples were collected from three different habitats:lake beach,farmland and flood control dike.The results showed that the food composition of A.agrarius was seeds (66.55±2.37)%,leaves and stems (19.01±2.13)%,roots of herbaceous plants (8.27±1.05)% and invertebrates (6.05±0.97)%.The diet of the animals was variable in different habitats and seasons,the proportion of seeds in its diet was lower when there was less seeds supply.The food composition between juniors and adults and between pregnant and non-pregnant females were significantly different in the same habitat and season.The results indicated that the animals could adjust their diet in different habitats and physiological periods.