17 indices are selected, such as the growth rate of total regional output value, the proportion of tertiary industry in GDP, per capita financial expenditure, and soil erosion rate of Guizhou Province in 2009. According to the relevant indices data of statistical yearbook and governmental website, by using the method of factor analysis and the method of cluster analysis, we assess the competitiveness of county economy in 88 counties of Guizhou Province. The results show that the competitiveness of county economy in Guizhou Province is impacted by factors of location and economic foundation. In addition, the resources environment, economic structure, economic developmental speed and other factors also impact the competitiveness of county economy in Guizhou Province. Based on these, in the light of the developmental characteristics of different counties in conjunction with different developmental advantages in different regions, we should adopt different developmental strategies according to local conditions, which is significant to rapid, healthy and sustainable development of county economy in Guizhou Province.