In the paper, we analyzed optimization algorithms for proxy signature and presented an optimized proxy signature scheme based on discrete logarithm cryptosystem. In the scheme, the signature entrusting parameters are generated with private keys of original signer and the proxy signer; dishonest proxy signer and outer adversaries can not attack secret parameters or other proxy signature with feasible polynomial algorithm, thus the scheme provides effective protection for the secrecy of proxy signers and also renders reasonable supervision on the proxy right. By utilizing random algorithms in signature generating, the scheme avoids the relevance between different parameters and proxy signature from the same signer. Then we presented an improved proxy signature scheme based on ECC (Elliptic Curves Cryptosystem), the scheme well satisfies the requirement of proxy signature and also makes full use of the superiority of ECC, such as high efficiency and security. Therefore, the scheme proves to be applicable to integrated environment with limited system resources.