In order to improve the fluid simulation speed based on the smoothed particle hydrodynamics ( SPH) ,a new grid-based neighbor search method realizing on the graphics processing unit ( GPU) is proposed. In this method,first,the particle grid map texture is created according to the particle position texture and is sorted according to the grid index of each particle via the CPU sorting method. Then,the particle neighbor index is obtained by searching the sorted grid map texture and is assigned to the pre-computed position of neighbor map texture. The proposed method overcomes the current inability of pixel shaders in terms of scatter operations. With the adoption of this new GPU-based neighbor search technology,SPH fluid simulation can be entirely implemented on GPU and the fluid simulation speed can be doubled.