In the existing threshold signature schemes, conspiracy attack is still a difficult problem to solved. To overcome the security weaknesses of Wang Bin's work and Wang Xin's work, a new scheme was proposed. In order to resist conspiracy attack, it utilized three ways: using model without a trusted part, it can eliminate authority cheating thoroughly and the security level was higher; adding random number and time stamp, it can prevent the attacker to recover the signer member's secret parameters and also to prevent the attack of disrupting protocol; using zero-knowledge proof verifiable method to confirm that the signer member had right secret parameters, so it can prevent the attacker to forge signature directly. The results show that this scheme is correct, and it can not only resist forgery attack and conspiracy attack, but also provide anonymity and traceability simultaneously.