Abstract: Wu and Shen point out that there is a weakness in the proxy multi-signature scheme based on elliptic curves discrete logarithm problem proposed by Ji and Li-using forgery attack，anyone of original signers can produce a valid proxy multi-signature.And based on it，a new modified and secure proxy multi-signature scheme is proposed by Wu and Shen.But it still unsafe，if several members collude together，they can make the agent-signature of signing some messages incorrect，because the proxy signature can be look as the proxy signature signed by proxy signer with some of the original signers.At the same time，honest members cannot detect this security flaw in the system，since the group can generate multisignature according to the prescribed protocols.So，a new proxy multi-signature scheme based on Chevbyshev is proposed.