In this paper, the propagation law of online teaching knowledge is studied by constructing a learner online teaching interaction network to characterize the position of each learner in this social network. The SI model is used to portray the knowledge dissemination process in the online learning interactive network, fully considering the two types of nodes of teachers and learners as well as the different transfer rates of knowledge dissemination of the two types of nodes, the SI model is improved, and the kinetic equations of knowledge dissemination are constructed. Finally, with the help of Matlab software to simulate the knowledge propagation process in the online English learning of teachers and students, the model was examined, corrected and analyzed, respectively, so as to put forward the optimization strategy of online English teaching interaction mode in colleges and universities. The results show that the path process from