In this paper, we propose a general stochastic model for the information dissemination on the online social network. The model considers the node of degree and propagation mechanism, utilizes complex network theory and dynamics of infectious diseases, and finally establishes the dynamic evolution equations. The dynamic evolution equations describe the evolution process of different types of nodes, and show that the propagation process is influenced by network topology and propagation mechanism. We simulate the information spreading process, and analyze the behavior of different types of nodes on online social network. Simulation results show that information can spread easily on the online social network because of the good connectivity. The greater the degree of the initial spread node, the faster the information spreads on online social network. Center nodes have great social influence, and the nodes with different degrees have the similar trend on online social network. Research shows that the model, having the same characteristics with online social network, contributes to a more profound understanding of information dissemination behavior on online social network.