With the construction of in-depth development of the market, the traditional fixed pricing model no longer suited to market-oriented economic development needs. In order to adapt to the current project bidding by the market needs of a project cost, we must work on the existing valuation methods and pricing model for reform, the implementation of projects bill pricing. Engineering is a list of pricing model and adapt to the market economy, allowing independent contractor pricing through market competition determine prices, with the international practice of pricing model. With the bill pricing model projects to promote, in accordance with international bidding practices is imperative. Therefore, "the lowest reasonable price of the successful bidder" My future is the most important evaluation methods. At this stage due to the implementation of projects bill pricing model and the problems mainly against China at this stage "招标投标法" in the minimum reasonable price of the principles of the successful bidder, most contractors have not yet set up their own enterprises of scale, companies unable to determine the reasonable Cost. This article is a scientific and fast set "reasonable cost" to study the key. First, from the project cost of the basic concept, of the engineering bill pricing model under the cost structure, to accurately predict costs of the project provided the basis, considering the average cost of the social cost to individual enterprises and the tender stage of the cost estimates. Followed through on fuzzy math and technology for smooth in-depth analysis, through "close-degree," the concept of reasonable fuzzy math and exponential smoothing technologies, construction of the project cost vague prediction model, and in accordance with the relevant information and statistics Information and experience to establish a "framework structure," the comparison works