|Digital certification can be used to substitute personal identification and verification of virtual would which was constructed by computer networks. And, proxy signature scheme can authorize proxy substitute the job in the condition of unleaking private key. Basically, proxy signature scheme have to pose the feature of privacy, distinguishing, security, and undenial. The main points of traditional proxy signature scheme are: to emphasis the receiver can verify the truth of proxy signature; to enhance the security of proxy signature scheme or declare the authorized paper to show proxy can substitute the job office ially. In the above method, the defect is that once the once the proxy gained authorized paper, then, he (or she) can use the right of proxy signature unlimitedly. This paper proposed a proxy signature scheme which can solve the problem of illegal using the right of proxy signature in unauthorized time period. In our scheme, the proxy don’t have to get the authorized paper, and, the authorized person can construct the proxy signature scheme with the authorized time period. Therefore, the receiver can verify the truth of the proxy signature, and also, check the time limit of proxy signature.