In order to study the particle shape characteristics and characterization method of manufactured sand, the particle shape of five kinds of manufactured sand was tested by aggregate image measurement system (AIMS) and digital image processing (DIP) technology. Based on the shortcomings of existing research, an improved particle shape measurement method was proposed, and the relationship between different particle shape characterization parameters was studied. The results show that the angularity of manufactured sand increases first and then decreases with the particle size range from large to small, while the two-dimensional shape value has no obvious change law. The manufactured sand in the range of 0.3~0.6 mm can reflect the angularity of overall particle size range. The particle shape parameters obtained by single projection image processing have a large fluctuation range, so it is impossible to accurately judge the particle shape of manufactured sand. Aspect has a strong correlation with convexity. Regularity has a strong correlation with aspect, roundness and convexity, while fractal dimension has no correlation with other parameters. The particle shape evaluation conclusion obtained by improved DIP technology is consistent with AIMS, which has certain feasibility and popularization value.