Since the single-sensor based head pose measuring system of the Helmet-Mounted Display (HMD) suffers from low accuracy and poor precision, a novel algorithm based on the information fusion of MARG sensor is proposed.First, the complementary filtering is combined with PI algorithm to estimate the gyroscope drift error, and then the pose data fusion is implemented by using the Extended Kalman Filter (EKF).We made experiments to compare the performance of the conventional single EKF and the proposed algorithm in filtering by using the measuring system composed of a CC1310, a gyroscope, an accelerometer and a magnetometer.The results demonstrate that the proposed algorithm can restrain the drift of the gyroscope and the noise of the accelerometer, and consequently improve the stability and precision of the head pose algorithm.