Abstract: [Objective] This study aims to explore the monthly dynamic changes and nutritional value of the three important grassland types in Xinjiang Shaertao Mountain and comprehensively rank the nutritive content of the three important grassland types (Stipa capillata + Achnatherum splendens, Iris ruthenica + Gramineae, Dactylis glomerata + herabarum varianum).[Method]The international standard method was used to measure the content of nutrients in the grass groups.The data were processed by SPSS 17, Duncan and membership function analysis.[Result]The result showed that the content of crude protein, calcium, phosphorus and total gross energy gradually reduced with the increase of month, while the content of acid detergent fiber and neutral detergent fiber tended to be increased.The order of comprehensive nutritive value during growth was May>June>July>August>September>October>November.The comprehensive nutritive value evaluation of different grassland types of vegetation was the third type(Dactylis glomerata+herabarum varianum), the second type(Iris ruthenica+Gramineae), the first type(Stipa capillata + Achnatherum splendens), respectively, in May and June.And from July to November, it was the second type, the third type, the first type, respectively.[Conclusion]According to the seasonal characters, the 3 important grass groups in the natural grassland in Xinjiang Shaertao Mountain in June and July have better utilization value.