In this paper, by converse using blind signature, we propose a practical electronic payment scheme for electronic commerce. This scheme is different from the existing schemes used widely in the Internet at present and it does not need the strong trust between customer and merchant. In this scheme, a semi-trusted third party (S-TTP) is introduced to provide a fair commerce environment. The S-TTP takes part in the protocol online and is not leaked any secure information about the business. Moreover, the users do not need to register to S-TTP. An advantage of the scheme is that this approach does not require the intervention of the third party in case of dispute, if one user cheats or simply crashes.