Project bidding and assessing aim at choosing the best bidder, and then achieve the best optimization of bidder's value aim. The current method of project bidding does not qualifiedly describe the connection among the quality, time limit for the project, and investment of engineering project, so it can not exactly evaluate the bidder's value aim. Consequently, this is not beneficial to achieve the best value. Value engineering is a function analysis method achieving the necessary functions at the lowest cost of total lifetime cycle. Based on the analysis of the existing issues in the valuating system, this paper provides some improvement on the current valuating methods and scientific basis for choosing the best bidder through calculating the value coefficient such as function, cost and value.