In order to provide theoretical support and decision basis for ecological protection in karst area， the evaluation method of ecological diversity service capacity in karst area is studied. Based on MODIS-NDVI data，meteorological data，land cover data，the net primary productivity (NPP) of vegetation were estimated in the karst area of Guangxi from 2000 to 2017 by using the light energy utilization model，and the spatial and temporal evolution characteristics of vegetation NPP in Karst area of Guangxi were analyzed.The spatial analysis model of climate resources in karst area of Guangxi is constructed using the method of climate equation，and the spatial and temporal distribution characteristics of climate resources in karst area of Guangxi are analyzed. The quantitative evaluation model of biodiversity maintenance function were established in Guangxi karst area based on NPP，and the spatial distribution characteristics of biodiversity maintenance ability in Guangxi karst region were analyzed. The service capacity of biodiversity in most areas of karst in Guangxi are relatively good. On the spatial scale of vegetation ecosystem types， the important characteristics of biodiversity maintenance function are as follows: shrub > farmland vegetation > grassland > others; On the spatial scale of cities and counties，the importance of biodiversity maintenance function shows a gradual increasing trend from south to north and from east to west. Important and extremely important areas accounting for 50.6%，mainly distributed in Baise，Hechi， Chongzuo，and the areas with national and municipal nature reserves. Generally important areas accounting for only 24.5%，mainly distributed in Guigang，Yulin，Guilin，Hezhou and Laibin，where natural disasters occur frequently and human activities interfere frequently. With high spatial resolution of NPP， quantitative assessment of biodiversity maintenance function can provide technical support for precise positioning of regional ecological protection space based on “3S”.