Abstract: A novel GPU acceleration method was proposed in this paper to improve performance of image composition in multi-GPU cluster node.The proposed method constructed an active pixel list by judging whether frame buffer pixels were updated.An index list was computed from the active pixel list using the GPGPU technology.Then the index list was used to conduct pixels composition on CPU.Given these operations,inactive pixel compositions could be totally avoided.Theoretical analysis show that the speedup of full image composition is determined by how many GPUs are configured in node and the proportion of active pixels to the full image.In the node with 4 GPUs,the speedup was about 3⁵ times when composited different images whose active pixels was about 12% to 76%.