Proper selection of secret parameters is essential to the security and feasibility of e-cash (electronic cash) scheme. In the paper, we presented an improved e-cash scheme with parameter optimization based on ECC (Elliptic Curves Cryptosystem). In the scheme, the secret parameters are generated with bionic optimization algorithm by a successive adaptive optimizing process. With the optimized secret parameters, the dishonest users and the outer adversaries can not attack e-cash with polynomial algorithms, so the scheme effectively prevents generalized ecash forgery and coalition attack. And the optimizing algorithm can be executed in advance without any influence to the efficiency of e-cash scheme. Besides, the algorithms of the scheme make full use of the superiority of ECC, such as high efficiency, short key length and etc. The optimization designing strategy of the scheme not only reinforces the security and feasibility of e-cash but also greatly improves the efficiency of e-cash for software and hardware application.