In the actual quantum communication,there are many non-ideal factors and some l imitations of experimental condition.In order to solve the above problems,this paper combines the powerful matrix operation function and the visual interface of MATLAB,and then develops the simulation program of quantum secure direct communication (QSDC) protocol.In the light of the trans formation formula of the four particle cluster state,this paper puts forward the preparation algorithm of four particle cluster state and the quantum secure direct communication protocol simulation algorithm based on the four particle cluster state,and also simulates its communication process.The consistency between the experimental result and theoretical result shows the security and validity of th e protocol,and proves the feasibility of using computer to simulate the quantum communication as well.The AS code is used to make some u nobservable quantum communication progresses visualization and promote the further development of quantum communic ation.