Abstract: Aimed at the problem of high-price auctions caused by bidders blindly raising prices during the auction of public resource userights, an online sealed auction scheme is designed by integrating credit value and the second price mechanism. This solution used the decentralized characteristics of blockchain and smart contracts to build a third-party auction environment. The use of the second price mechanism combined with credit value management to achieve a sealed auction, encouraged bidders to bid with their true will, and avoided vicious competition caused by blind bidding when information was asymmetry. We proposed an improved sealing scheme to enhance bidding privacy and simplify auction result verification process. Analysis and experiments show that the proposed scheme can constrain the bid price within the expected range and meet the auction safety and performance requirements.