Fast and accurate estimation of global motion is necessary in target tracking，video coding and etc.Considering the global motion estimation of video with both camera motion and foreground objects motion，a new global motion estimation algorithm is proposed.In the algorithm a three-level pyramid is utilized.Then outliers are effectively eliminated with the block-based methods in the calculation of each pyramid level.In order to accelerate the algorithm，4-Queen and 8-Queen patterns are also used to sample background pixels respectively on the intermediate level and the base level，and only the extracted pixels are contributed to the iterative calculation.The experimental results show that the algorithm improved the estimation speed greatly without reducing the accuracy and satisfied the real-time request.