Reservoir resettlement project is an important part of the whole water conservancy project. The smooth implementation of resettlement will directly affect the implementation of other projects in dam areas and reservoir areas. In this paper, an example of an immigration project in China is used to establish GM (1, 1) model with grey system theory. The deviation forecast and analysis of the six migration population data in the three years of the project are made, and the rationalization suggestions are put forward. The purpose is to make the resettlement department timely and quantitatively understand the deviation of resettlement progress, and provide an effective basis for the progress control of the whole project so as to promote the resettlement work as planned. The analysis results show that the model is highly accurate in predicting the deviation of resettlement progress of reservoir resettlement and can be used for medium and long-term predictions. At present, the relocation and resettlement work of the project is lagging behind the planned completion time, and effective measures should be taken to speed up the progress of the project.