Abstract: Based on the MODIS NDVI data of the growing season in 2000-2014 and the grid data of average temperature and precipitation during the same growing season, the trend analysis method, SPEI index and correlation analysis method were used to analyze the temporal and spatial variation of NDVI and its response to climate change in Sanjiang Plain. The results show that the NDVI value of the Sanjiang Plain in the past 15 years increased slowly at a rate of 0.017/10a. Among them, the proportion of NDVI significantly increased and extremely significant increase was 13.43% and 12.55%, respectively. The area of slight improvement in NDVI trend is relatively large, at 25.52%; The average annual temperature in the Sanjiang Plain growing season showed a downward trend, and the precipitation increased. The overall SPEI value of the growing season showed an upward trend, the aridification weakened year by year, the moderate drought condition was alleviated, and gradually transitioned to a slightly humid state. The increase in coverage has a positive effect and provides favorable conditions for ecological restoration in the region; In the growth season of the Sanjiang Plain, NDVI was mainly positively correlated with temperature, precipitation and SPEI in the growth season, accounting for 72.64% of the area positively correlated with precipitation, 70.51% with SPEI and 56.73% with temperature. NDVI has the highest correlation with precipitation, indicating that precipitation is the dominant climate factor for vegetation growth in the Sanjiang Plain.[

Key words: MODIS NDVI, climate factor, SPEI, trend analysis, Sanjiang Plain