Abstract: Land reclamation is an important measure for the sustainable usage of land resources in mining area. The work of land reclamation in china begins rather later and lacks of new techniques and theories, which has affected the development of land reclamation. The application of extension method to land reclamation in mining area can improve the decision level for planning. The relative description for land reclamation is firstly analyzed based on the extension method, and then a land suitability evaluation method based on the extension method is given, which is tested by an example. The result of test demonstrates that this method can obtains good result, which is more accordance with fact. The advantages of this method are that it cannot only overcome the effect of man-made but also can quantify factors, then improve the evaluation precision. The extension method will have an extensive application field in land reclamation of mining area.