At present most practical electrical auction schemes that based on secret sharing, group signature and hash chain assume the existence of a trusted thid party, while the schemes that based on commitment, zero knowledge or homomorphic encryption without the TTP model face the problem of high cost of communication and computation. The double auction scheme proposed by Bogetoft is based on secure multiparty computation without a TTP and get very high efficiency. In this article, we improve the above scheme. Based on secret sharing and constant round safe comparing protocol, we reduce the requirement of honest majority in the original scheme. We improve the security of the scheme while maintain the high efficiency.