Abstract: Interactive fluids simulation and rendering have been the pursuit for VR research. There are high demands for physically plausible fluids in virtual environments. In this paper, we present an efficient GPU-based simulation and rendering framework for large scale SPH fluids. A robust particle classification algorithm is introduced to classify particles into either active or inactive. And the proposed algorithm effectively reduces the computational burden in inactive areas where many particles with stable properties and low local pressure cluster together. At the same time the computation in active areas is fully carried out to preserve the realistic behaviour of fluids. Our time performance tests have shown that our algorithm has high capability in producing time efficiency fluid simulations. When integrated with the parallel HPMC method, we are able to put all the simulation and rendering on GPU, and produce plausible and interactive fluids for large scale virtual environments.