Bed material is composed of sands and gravels with different sizes and shapes, and affects the bed roughness, and habitat morphology, Traditional methods for analyzing the bed material grain size distribution are labor intensive and time consuming. Recent advancement in digital technology makes it possible to sample the bed material with digital cameras and quantify the grain size distribution with image processing and analysis software; thus significantly improves the sampling efficiency and lowers the costs. In this work we first introduce the only available photo-sieving software that is specifically designed for bed material grain size analysis, and perform parameters calibration. Eight combinations of uniform and mixed-size grains with dry and wet conditions are used to test anti verify the software. The results clearly indicate the feasibility of the photo-sieving software foe the grain sloe analysis. Some practical suggestions ace also proposed for future applications of the software.