Abstract: Based on the observational data of natural grass in Zoige region from 1983 to 2013 and the surface meteorological observation data over the past 50 years, we have analyzed the characteristics of climate change in the researched area and its impact on the growth period of alpine bluegrass (natural grass) with trend and correlation analyses, M-K mutation test, integral regression and other mathematical methods, so as to reveal the response regularity of the growth period of natural grass in Ruoergai Wetland to the climate change. The results show that: (1) The annual precipitation in the researched area has slight decrease trend, and the downtrend of effective precipitation days is the most significant in the critical growth period of grass (from May to September). The annual average temperature, maximum and minimum air temperatures possess a significant increase trend, so does the cumulative temperature month by month in growing season of grass (from April to September). The drying index in the grassland rises with the rate of 0.0256/10a, and warming and drying have been exacerbated since the mid-1990s. (2) Periods of reviving, tillering and earring in the 2000s were earlier than those in the 1980s, and the flowering period has delayed 4 days compared with that in the 1990s. The brownoff period was 12 days ahead of that in the 1980s and 9 days later than that in the 1990s. The growth period in the 2000s has reduced 20 days compared to that in the 1980s and increased by 8 days than that in the 1990s. (3) The cumulative temperatures was ≥ 0℃ in March, and that ≥ 3℃ in both April and June with significant increase, resulting earlier periods of reviving, tillering and earring of grass. The more effective precipitation days are, the earlier the growth period is, vice versa. And this is true for all periods with an exception of the reviving period. (4) The growth period of grass is sensitive to meteorological factors such as the average temperature, daily temperature range and effective precipitation days. If there is no or lighter drought in July-the critical period of grass growth, the growth period will be prolonged due to climate warming.