Abstract: This paper presents a GPU based algorithm for rendering participating media with single scattering.First, the algorithm efficiently determines the ray marching path using the intersection points list of ray tracing and intersection points of the ray and the bounding box of the media, and then it calculates single scattering lighting through ray marching, which parallelizes the media single scattering rendering procedure.Based on the parallel algorithm, this paper proposes an image space interpolation approach to accelerate the rendering process.Based on the observation that rendering single scattering only depends on the depth of ray marching, the distance from the sample to the light source, and the local property of media, we make an interpolation approximation in image space by choosing a proper interpolating function, which can decrease times of ray marching and save rendering cost.Without any pre-computation, our algorithm achieves an interactive performance.Moreover, the algorithm supports changing the property of the lighting and the media property on the fly.In addition, the algorithm can handle various materials of media including homogeneous and heterogeneous with anisotropic phase function.