Aiming at the suitability grade assessment problem for rural tourism development, an assessment method based on TOPSIS is proposed. Firstly, the suitability grade assessment problem for rural tourism development is described, and the index system and grade division of rural tourism development are proposed. Then, the membership functions based on grade division are constructed and the weights of indexes are computed. Furthermore, the closeness degree of each scheme on different levels based on the TOPSIS are calculated. Computing their grade characteristic values, the suitability grades of rural tourism destinations are determined by using two-tuple semantic method. Finally, a rural tourism destination is taken as an example and the analysis results are also given. It is shown that the proposed TOPSIS model and method can sufficiency reflect the essential requirements and characteristics of the concept of grade evaluation and efficiently overcome the issues resulted from the commonly-used linear weighted average grade evaluation method and maximum membership degree principle. The proposed method not only makes the results more rational and reliable but also can distinguish the difference of the identical grades. It can provide a new method of quantitative computation and qualitative analysis for the suitability assessment of rural tourism development and generalizes the TOPSIS in multiattribue decision making.