Abstract: Aiming at the problem of the extraction of line of sight interfered by missile attitude of phased array radar seeker. A decoupling algorithm based on adaptive Kalman filter is proposed, which introduces a suitable forgetting factor to optimize the performance of the filter. The mathematical model of recursiving and predicting noise characteristics is established and filtering equations and noise estimation equations are combined to solve the problem of decoupling of line of sight angular rate, so the angular rate of the line of sight is extracted within the allowing scope of the error. Finally, simulation results show that the proposed algorithm is effective in the problem of strapdown decoupling and is more accurate than the standard Kalman filter algorithm, which improved the accuracy of line of sight rate extraction, optimize missile guidance performance, and have high engineering application value.