Aiming at adverse effects resulted from system error on state estimation precision in linear system ,a novel target tracking algorithm based on joint estimation of system error and state was proposed in Kalman filter framework. Firstly,the influence of system error on target state estimation and state estimation error covariance matrix were ana— lyzed quantitatively.Secondly,combined with the extension method of state dimensions,the registration process of sys— tem error was constructed.Finally,the realization steps of new algorithm were designed according to the iterative process of standard Kalman filter.Simulation results show the feasibility and effectiveness of new algorithm dealing with system error registration and state estimation when system error is constant or time-vary.