An evaluation system for wavefront of laser is introduced by shearing technology. The triangle shearing interferometer and one step differentiation method are selected considering the characters (quality of wavefront, power and scale of light spot etc.) of dye laser. Automatic analysis and intelligence technologies for shearing figures are discussed. Which include calibration of system, auto-correcting of shading, threshold selecting aided by histogram analysis, etc., so that human intervention is displaced in normal testing process. The repeatability of system is 0.02λ, and accuracy is 0.05λ (RMS).