Chaotic dynamics is sensitively dependent on the parameters,which is used for parameters identification and chaos synchronization. The drive response structure is employed,and the parameters of response system are adaptively adjusted to minimize synchronization error according to the predefined quadric index function and the corresponding optimizing methods. The unknown parameters of the drive system are identified and chaos synchronization between drive system and response system is achieved by the proposed method. The control experiments with quasi Gauss-Newton method,Hook-Jeeves method and conjugate gradient method are carried out. Discrete Hénon system and continuous Lorenz system with two unknown parameters are used as simulation examples,and the simulation results show that the conjugate gradient method possesses better performance,which can be further used to decode chaotic shift key secure communication.