Remote Sensing Application Centre (RSAC) has been working on monitoring the main crop planting areas as an operational task and a research project based on its system for several years. A problem has been proposed from the RSAC’S technology system, which is that the monitoring result is only an estimate to main crop planting areas without quantitative explanation to crop area change reasons. The study as a project approved by RSAC attempts to solve the problem. A survey index system about crop area change reasons has been established by questionnaire and expert consultation. Through further research, 9 driving factors of crop area change have been set up by assembling 5 survey indexes. Based on triangular whitenization weight function of grey system theory, the crop Area Change Driving Model (ACDM) was designed. The factor weights and factor grey classes were produced through expert consultation. Heilongjiang province as the experiment region and single cropping rice as the experiment crop were selected in this study. The experiment result produced by ACDM is consistent with the estimate produced in monitoring crop area by RSAC in 2013.