Key management is essential to the security of a cryptosystem. In the paper, we introduce bionic evolution into the designing of key management schemes, and present an improved key management scheme based on bionic optimization algorithm. In the scheme, the private keys of CA (Certificate Agency) and KDC (Key Distribution Center) are generated with an adaptive optimization algorithm according to the optimization principles of bionic evolution. The optimization algorithm avoids the indefinite security problems in private key selection, and effectively prevents certificate forgery and coalition attack by dishonest users and other adversaries. And the optimization algorithm can also be applied to generate other secret parameters in advance. The algorithms of the scheme take great advantage of the superiority of ECC (Elliptic Curves Cryptosystem), such as high efficiency, short key length and etc. The designing strategy not only reinforces the security, stability and robustness of key management scheme but also improves the application efficiency regarding software and hardware environment.