Abstract: As an important parameter of terrestrial ecological processes, leaf area index (LAI) is of great significance to the ecosystem’s carbon cycle and regional water and soil conservation. Based on MOD15A2H/LAI data set from 2001 to 2018, the spatio-temporal distribution pattern and change trend of vegetation LAI were studied. Then based on the meteorological data, land cover data and DEM data, the response of LAI to climate change was analyzed emphatically by using Theil-Sen media analysis method, Mann-Kendall testing method and correlation analysis method. Results showed that: (1) the mean value of vegetation LAI was 1.22 with a spatial distribution feature of high in the south and low in the north of HM from 2001 to 2018. (2) Vegetation LAI is affected significantly by topography factor. Vegetation LAI presented a feature of “elevation-down-stability” with elevation increasing, while vegetation LAI value showed an upward trend with increasing of the slope. (3) In the recent 18 years, the vegetation LAI increased at a rate of 0.07· (10a)^-1, among which 68.92% showed an increasing trend and 31.08% showed a degradation trend. (4) The LAI was found to be positively correlated with air temperature and sunshine duration, while negatively correlated with precipitation. At the significance level of P<0.05, the areal proportion of significant correlation LAI with air temperature, precipitation and sunshine duration were 22.7%, 33.58%, and 31.80%, respectively, which indicating precipitation and sunshine duration were the dominant climate factors on LAI, and air temperature on LAI was weaker relatively.