The characteristics of cutter frame of topological structure on general purpose lathe were analyzed systematically. Based on the multibody system theory and the homogeneous coordinate transformation principle, taking an example for CA6140 lathe, a geometric error model for lathe cutter frame system was established through using Matlab programming. Through using manmachine interactive input method, geometric error modeling and analyzing on cutter frame system were quickly done on tha cutter frame system. The analysis results of error sensitivity and error regularity can be used as important basis for tolerance design and stiffness distribution on cutter frame system.