[Objective] This paper studied spatial-temporal characteristics and the influence factors of carbon capture by crops in Shaanxi Province during the recent twenty years in order to provide a reference for the research of regional ecosystem carbon cycling. [Methods] Based on the data of yield and planted acreage of major crops, and other else, coefficient method and gray correlation model were used to estimate and analyze the spatial-temporal characteristics. [Results] (1) The amount of carbon capture by major crops showed a fluctuated trend from 1991 to 2012 in Shaanxi Province. The amount of carbon capture by food crops was bigger than that of carbon capture by economic crops. Annual fluctuation of carbon capture by food crops was also more stable than that of carbon capture by economic crops. (2) There were obvious spatial differences in the amount of carbon capture by main crops and its change in Shaanxi Province. They were summarized as follows: Guanzhong region > South region of Shaanxi Province > the Loess Plateau in North Shaanxi Province > sand drift region in North Shaanxi Province. The amount of carbon capture by crops in three regions increased, except the south region of Shaanxi Province. The gravity center of carbon captured by major crops in Shaanxi Province mainly located in the districts of Xi'an and Xianyang area, showing a change trend from southwest to northeast. (3) Crops' effective irrigation area, harvest guaranteed coverage despite of drought and waterlogging, and planting area were the major factors on carbon capture by crops. The correlations between various factors and carbon capture by major crops were found spatially different. [Conclusion] Crops play an important role in carbon fixation in growing process, but its growth rate of carbon capture by major crops in Shaanxi Province is less than that of carbon capture by major crops in most parts of China. Improving effective irrigation rate and artificial input can help to increase the amount of carbon capture by main crops, and to alleviate the pressure of regional carbon emissions.