The invention discloses a cast steel member detection method based on BIM technology. The method is characterized by outputting the profile map of any position by creating a cast steel member BIM deepening model in order to facilitate design idea grasp for technical workers and increase cast steel member processing efficiency; scanning and detecting a cast steel member wood model and a cast steel member product by using a handheld 3D laser scanner with precision of 0.1mm, generating a spatial 3D model by inverse imaging and performing theoretical BIM model fitting analysis; expressing a detection result in the spatial 3D model in a chromatogram way, outputting single-point area deviation values, deviation trend, and an error range, achieving clear deviation value, and significantly increasing measurement efficiency. The method increases the processing efficiency of the cast steel member, prevents a waste of field construction resource due to processing errors, and provides protection for field installation.