A PLKF(pseudo-linear Kalman filter) was presented for tracking a moving target by using multi-stations of IRST systems.The initial value of the filter was attained from the pseudo-linear equations,which improves the tracking accuracy and speed of the filter.Results of the simulation of tracking a moving target by PLKF and EKF(extended Kalman filter) illustrate: for 3 or 4 stations,the tracking accuracy of PLKF is more advantage than that of EKF at the beginning of the tracking;for 6 stations,the PLKF and the EKF have the same tracking accuracy.