Because of climatic diversity in China whose latitude and longitude span more than 20◦, there are four main peanut producing areas in China (Ding et al., 2012). The aim of this research was to investigate the incidence of aflatoxin contamination in peanuts at harvest under different agro-environmental conditions in China and its relationship with climatic conditions. This research would provide technical support to establish an early warning mechanism for large-scale detection and would be important for reducing pre-harvest aflatoxin contamination of peanuts.