The cost of power plant water supply and drainage system accounts for a large share in the proportion of project investment. If the determination of its installation cost can be realized intelligently, the work efficiency and accuracy can be greatly improved. The system includes a combined pump house, a drain- age siphon well, and a number of major supply and drainage galleries, among which the combined pump house uses the production capacity index method and the drainage siphon well uses the proportion estimation method to realize the intelligent determination of installation project cost by establishing the relevant reference project database and using limited input parameters, while the main supply and drainage gallery cannot be realized due to the excessive correlation with the site layout.