Abstract: In order to study the tissue structure and glycogen distribution in the liver and kidney of Tibetan sheep and small-tail Han sheep, liver and kidney tissues were collected from healthy adult Tibetan sheep reared at an altitude of about 3 500 m and healthy adult small-tail Han sheep reared at an altitude of about 1 500 m. The tissue structure and indexes（hepatic histological indexes included the thickness of liver capsule, the area of liver lobules, and the proportion of glycogen distribution, while renal histological indexes included the number of glomerulus per unit area, the glomerulus area of kidney, the diameter and the epithelial cell area of renal tubules, and the proportion of glycogen distribution） of liver and kidney of Tibetan sheep and small-tail Han sheep were studied by conventional paraffin section combined with H.E., Masson and PAS staining. The result showed that the average thickness of the liver capsule of Tibetan sheep（138.5 μm） was significantly thicker than that of the small-tail Han sheep（115.5 μm, P＜0.05）, and the average area of liver lobules（0.268 mm~2） was significantly smaller than that of the small-tail Han sheep（0.311 mm~2,P＜0.05）. The glomerulus area of kidney cortex in Tibetan sheep（9 528.2 μm~2） was significantly larger than that of small-tail Han sheep（4 016.8 μm~2,P＜0.05）, and the number of glomerulus per unit area was higher than that of small-tail Han sheep（P＞0.05）. The average diameter of renal tubules and the epithelial cell area were significantly higher than those of small-tail Han sheep（P＜0.05）. In the PAS staining of the liver, the PAS reaction of the hepatocytes of Tibetan sheep and the small-tail Han sheep were positive. The strongest PAS positive reaction was found in the central vein, portal area and liver capsule. In addition to the above areas in the liver of Tibetan sheep, there was also a large amount of glycogen accumulation near the liver plate. In the PAS staining of kidneys, most amount of the glycogen was distributed on the basement membrane and mesangial cell matrix of the renal tubules of Tibetan sheep and the small-tail Han sheep. The cytoplasm of the epithelial cells of proximal convoluted tubules contained glycogen, and the stronger positive sites were at the base of the cells and the brush border. The proportion of glycogen distribution in the liver and kidney of Tibetan sheep was significantly higher than that of small-tail Han sheep（P＜0.01）. The results indicated that there was a great difference in the tissue structure of liver and kidney of Tibetan sheep and small-tail Han sheep, and there were more glycogen distributions in Tibetan sheep.