The cultivated land quality grading results are an important reference for the implementation of the trinity protection of cultivated land quantity, quality and ecology. Crop production potential index is one of the most important parameters in the evaluation of cultivated land quality, and its accuracy determines the scientific nature of the survey results of cultivated land quality grades in China. By using the method of geodetector, a total of 70 counties, including Ping’an county and its surrounding counties were used as research objects to detect the interpretation of production potential index by different stratification methods of topography and meteorological factors, and revise the production potential index of appointment crop. The key results were as follows: in the study area, the factors that significantly affected the crop production potential index were altitude and annual average rainfall;the stratification method of altitude with the highest explanatory power for crop light temperature production potential index was based on 1100m, and 200m as interval;the stratification method of annual average rainfall with the highest explanatory power for crop light temperature production potential index was based on 0mm, and 100mm as interval;for the climate production potential index, the stratification method of altitude with the highest explanatory power was based on 1100m, and 200m as interval, and the stratification method of annual average rainfall was based on 25mm, and 50mm as interval. According to the correction result of Ping’an county, the crop light temperature production potential index was reduced to a different extent compared with the light temperature production potential index used in cultivated land quality grade survey and evaluation;while the climate production potential index was generally rose. Using the model proposed, natural grade of nonirrigated cultivated land was rose overall, but natural grade of irrigated cultivated land was reduced in different extents.