Abstract: The aim of the present study is to develop an efficient image processing approach and flow field reconstruction method to obtain the particles velocities distributions from a single frame and single exposure image (SFSEI). The image processing approach contains de-noising, laplacian sharpening, adaptive threshold segmentation, close operation, removing of small particles and skeletonizing; the velocity calculating algorithm contains velocity calculating, ambiguity estimating, tangent vector calculating. The error produced by these methods is calculated. The flow field reconstruction approach is based on RBF (Radial Basis Function) interpolation and optimized by windward interpolation, the deviation of the reconstruction method is also calculated. A processing example using jet flow image demonstrates that the algorithm is practicable.