According to the natural features, ecosystem functions and social human indicators, the paper constructed the health assessment indexes of Chengjiang watershed karest ecosystem. Using the multifactor hierarchical fuzzy assessment method, the paper assessed the comprehensive health condition of the watershed ecosystem, then concluded that: the natural feature system health of Chengjiang watershed is 0.48, ecosystem function heath is 0.48 and social and human system health is 0.448, the whole watershed ecosystem health is 0.472. According to the gradation of assessment standard, the ecosystem health condition of Chengjiang watershed is sub-health.