The goal of this paper is to develop a numerical approach for fresh concrete's flow, by using the mesh free method, called Smoothed Particle Hydrodynamics (SPH), and a new rheological model named VGM (viscous granular material) model, which can describe the nonlinear, shearing time-dependent, and pressure-dependent characteristics of the flow behaviors of fresh concrete. Moreover, the visco-plastic model proposed by Murata was adopted to treat the slippage resistance of fresh concrete at its flow boundary. Next, the flow behaviors of fresh mortar in the L-flow test were observed experimentally and simulated numerically. As a result, it was found that VGM model is more accurate than Bingham model for simulating the flow of low fluidity mixture, since the former can reflect the change of internal structure of fresh concrete during the flow process.