Abstract: In order to observe and analysis the differences in the morphology and size of blood cells of Dulong chicken of different sexes, blood samples were collected from 10 healthy Dulong chickens aged 24 weeks（half female and half male） with body weight of 1.5-1.8 kg. Wright-Giemsa staining method was used to stain blood cells, and the morphology was observed under a microscope and the pictures were taken for preservation. The size of blood cells（including red blood cells immature red blood cells and mature red blood cells and white blood cells basophils, eosinophils, neutrophils, monocytes and large and small lymphocytes） were measured with Motic Images Plus 2.0 ML software, and the number of the above blood cells was counted manually. The above indicators were tested by independent t test for sex differences. The results showed that the mature red blood cells of Dulong chicken and its nucleus were elliptic. Immature red blood cells were nearly ovoid or elliptic, and the nuclei were nearly elliptic. The neutrophils were round or elliptic, and the nuclei were mostly lobulated, generally 2 to 5 leaves. The eosinophils were round or elliptic, and the nuclei were obviously lobulated, usually 2 leaves. The basophils were round or elliptic, and the nuclei were not clearly lobulated. The monocytes were large in size and nearly round, and the nuclei were irregular, most of them were horseshoe-shaped and kidney-shaped. The large lymphocytes were slightly smaller than monocytes and were nearly round. The small lymphocytes were nearly round and were the smallest cell in white blood cells. The thrombocyte of Dulong chicken often gather together in three or five to form a larger block structure, and the nuclei were round, oval or irregular. The length diameter of mature red blood cells of male Dulong chicken were significantly lower than that of female（P＜0.05）, and the short diameter of mature red blood cells were extremely significantly smaller than that of female（P＜0.01）. However, the long and short diameters of immature red blood cells of male Dulong chicken were extremely significantly larger than that of female（P＜0.01）. The length diameter and short diameter of neutrophils and basophils in male Dulong chicken were significantly larger than those in female（P＜0.05）. There were no significant differences in the length diameter and short diameter of eosinophils and monocytes between different genders of Dulong chicken（P＞0.05）. The length diameter and short diameter of large and small lymphocytes in male Dulong chicken were extremely significantly larger than those in female（P＜0.01）. In the white blood cells of Dulong chicken, the number of small lymphocytes was the largest, followed by large lymphocytes, monocytes, neutrophils and eosinophils, and the content of basophils was the least. There was no significant difference in the number of red blood cell and white blood cell between different genders Dulong chicken（P＞0.05）. These results indicated that the oxygen transport capacity of red blood cell of Dulong chicken was different between males and females, and the immunity of male Dulong chicken was stronger than those of female Dulong chicken.