Abstract: Full process circled simulation flat of some missile turbojet and its oil supplied regulating system based on MATLAB is proposed for factually describing component interaction of engine system.The adopted engine model is built by methods of combing aerodynamics and thermodynamics theories with neural network,and oil supplied regulating system is modeled by methods of mechanism analysis and parameter identification.On the flat,we analyze the effect of diaphragm characteristic upon engine starting and accelerating performance.The results indicate that the circled simulation flat is of high reliability,and it can reflect the actual working process of the turbojet and its oil supplied regulating system.