Abstract: Real-time human-like avatar behavior in virtual environments makes important contributions to the realism of VR worlds. The existing human-like animation approaches demand intensive calculations and graphics rendering. Complex 3D avatar models are usually constructed with thousands of triangles, which slow down the rendering rate. In this paper, we present an impostors-based approach to achieve the real-time human-like avatar behavior in virtual environments. Theoretically, our method animates any human-like behavior in virtual worlds without creating a 3D avatar model. Experiments show that this approach consumes less time in both calculation and rendering, and thus leaves more CPU time and hardware resources to other tasks. It brings a substantial improvement to avatar behavior in VR worlds.