Grassland is an important natural resource in the Xiliao River Plain, Northern China because of its ecological and economic importance. The overexploitation of groundwater makes it necessary to understand the influence of groundwater decline on grassland vegetation growth in this region, especially in the context of climatic change. We aimed to identify the main factor affecting the grassland growth through integrated analysis of grassland impact factors. Changes in normalized difference vegetation index, groundwater depth, precipitation, and temperature were analyzed during 1982 - 2013 in Xiliao River Plain. A correlation analysis was conducted among groundwater depth, precipitation, temperature, and normalized difference vegetation index using Pearson correlation equations. Results indicated that precipitation became the main influencing factor of grassland growth instead of groundwater depth due to the increase of groundwater depth after 1999. This shift might pose a threat to the survival of grassland growth during a long drought period. Therefore, groundwater change issues should be gradually integrated into future policies and strategies for grassland development and management.