To meet high precision digital measuring of robot in-situ milling for aircraft assembly, the bilateral filtering processing and fast data simplification algorithms were studied for 3D point cloud software used to data acquisition and processing was developed, based on which 3D point cloud were processed including to denoise and simplify. The method of point cloud processing in this paper reduced the damage of filtering to boundary features, and saved effectively key features of complex components including round corner, rib and boundary of spatial curve. Taking typical samples as test objects, the methods of point cloud processing were tested to compare with CMM measurement results. Developed software realizes efficient integration with automation equipment, has high openness of software interface, avoids a lot of human-computer interaction, reduces data processing time, and meet the timeliness requirements of robot in-situ milling equipment.