Evaluation of regional tourism competitiveness has been a hot issue of tourism geography and regional economics in recent years. This study introduces system theory and Professor Porter’s National Diamond Model into constructing the evaluation index system of regional tourism competitiveness, which includes four decisive factors, namely production factor, market, industry and support competitiveness. And by comprehensive use of subjective and objective methods like Principal Component Analysis (PCA) and Analysis Hierarchy Process (AHP) the appraised values were calculated. At the same time, the method was applied to dynamic demonstration analysis of the tourism competitiveness of the provinces in Southwest China from 2001 to 2005. The result shows that their tourism comprehensive competitiveness has distinct differences. The comprehensive competitiveness of Sichuan and Yunnan are better, Chongqing and Guangxi are in the middle, and Guizhou and Tibet are weak. According to the competitiveness ranks in 2001-2005, comprehensive, production factor, industry and support competitiveness changed a little and market competitiveness changed a lot. This competitive pattern has been made mostly because natural resource conditions and economic development levels of the provinces are very different and are difficult to be changed in a short period. Evaluation of regional tourism competitiveness has has a a hot issue of tourism geography and regional economics in recent years. This study introduces system theory and Professor Porter’s National Diamond Model into constructing the evaluation index system of regional tourism competitiveness, which includes four decisive factors, namely, production factor, market, industry and support competitiveness. And by comprehensive use of subjective and objective methods like Principal Component Analysis (PCA) and Analysis Hierarchy Process (AHP) the appraised values ​​were calculated. At the same time, the method was applied to dynamic demonstration analysis of the tourism competitiveness of the provinces in Southwest China from 2001 to 2005. The result shows that their tourism comprehensive competitiveness has distinct differences. The comprehensive competitiveness of Sichuan and Yunnan are better, Chongqing and Guangxi are in the middle, and Guizhou and Tibet are weak. According to the competiti veness ranks in 2001-2005, comprehensive, production factor, industry and support competitiveness changed a little and market competitiveness changed a lot. This competitive pattern has been made because natural resource conditions and economic development levels of the provinces are very different and are difficult to be changed in a short period