Water conservancy and hydropower engineering construction system is a typical multi-level complex system and its swarm identity is apparent to brittleness cumulative effect. The brittle sources are interlinked and associated, thus there are topological forms of different brittle sources, which make the relationship of brittleness evaluation cumulative function to be non-linear. In traditional evaluation methods, indicators are usually assumed to be independent, which does not satisfy the non-linear characteristics of water conservancy and hydropower engineering construction system brittleness. Thus, in this paper, weak monotonic of fuzzy measure is used to replace the addition function, brittleness evaluation model of water conservancy and hydropower engineering construction system based on Choquest integral is built.