Abstract: The assessment index systems for construction, channel maintenance and research are developed according to the features of each project category and the weights for the indexes are defined. Non-bias rectangular distribution function and F-test is used to determine the membership degree of measurements of indexes, which are confirmed according to trapezoid membership function in favor of upper or lower deviation, depending upon the type the index belong to, cost type or profit type. The resultant assessment is obtained with F comprehensive evaluation model. The final score and grade are decided against the set critical values. The assessment process of a construction project is presented as an example.