Abstract: To improve the autonomous operation of excavator's attachment and reduce the intensity of operator's labor, an I-FORMA-O approach was presented for the behavioral control of the princpal actions of a PC02 excavator to be implemented and for developing a simulating model based on Fuzzy Logic/Stateflow. The Simulink experiments verified that the state-transition process of excavating behavior is resulting from the events which were driven by the correspoding principal actions. And the result showed that the principal actions defined by Fuzzy Logic simplifies the computation and that the model as a platform is visual, reliable and available to resort to drivers' operating experience for the excavator or modify it so as to improve the R and D efficiency. Thus, a foundation is laid to directly generate an executable code for the applications of RTW (real-time workshp) tool kit.