The study presents a new realistic rendering algorithm for a fluid scene with SPH (Smoothed Particle Hydrodynamics) in a screen space. First, the paper proposes an anisotropic based surface smoothing model: The study adopts the Laplacian Smoothing to acquire relative smooth particle position distribution in 3D space. Next an anisotropic modal is used to produce initial fluid surface. Last, a bilateral filtering depth map, we got the final desired smoothing fluid surface. Next, the study present a finer fluid surface illumination model to improve fluid scenes rendering, also using curvature based model to add realistic details of fluid. The study realizes that all these are in GPU. Compared with other methods, the approach can greatly improve the realism of fluid scenes rendering in screen space without losing the real-time performance, and could be found great potential applications in the domains such as real-time simulation and game, etc.