Abstract: In view of the complicated,inaccurate and nonintuitive problems of drawing the phase trajectory in the course of teaching and teaching experiments,this paper uses Simulink and graphical user interface (GUI) to design and develop a teaching simulation platform for the phase trajectory of nonlinear system.On the platform,the nonlinear system simulation model constructed by Simulink can be set up,and the system parameters can be set or modified interactively so as to realize the plotting and analysis of the phase trajectory of the nonlinear system.The practice results show that the teaching simulation platform can solve the above problems with good interaction and simple operation.It can not only enrich teaching methods,but also stimulate students' interest in study,cultivate students' research and innovation ability,improve teaching effect and improve teaching quality.