The superiority dimension-forces which network has make information diffusion in realistic space change in the nature through information coupling. It means that information diffusion in realistic space is no longer affected by geography, volume and time constraints. Under the promoting of network dimension force, the source information can reach any sink fast and synchronously in broad spatial scope and accumulate information instantaneously to surmount the threshold value of sink, and then realize the diffusion distance willfully far, the quantity of information destination willfully more, the diffusion effect obviously enhanced. In order to measure the diffusion effect under the promoting of network dimension force, on the basis of the core idea of the network dimension-force theory, using for reference from the Markov drift chain theory, this paper carries on the model construction and simulation of information diffusion. This model attempts to describe systematically and semantically the motion state of information diffusion from the macro level, and the simulation results reveal the positive promoting role of network dimension-force on information diffusion.