Based on the efficient market theory in information economics and institutional economics， information disclosure and its effects on market efficiency， transaction cost， transaction velocity and market fairness are analyzed， from the new view of information disclosure effectiveness. Then the evaluation indicator system of electricity market information disclosure is established according to the subjects and principles of information disclosure. Applying this evaluation indicator system， characteristics and suitable environments of two main transaction modes， i.e. bilateral trading and centralized trading are compared. The conclusion is that the mid-long term bilateral trading should be the chief transaction mode， and spot centralized trading the assisted one according to national conditions， actual market environment and transaction target in China.