Abstract: Physical analog simulation experiment is one of the main methods to study the mechanism of coal and gas outburst. Due to the development of large-scale outburst simulation experimental devices, the demand for the mechanical loading capacity of this devices is increased. By statistically analyzed the types and characteristics of the existing mechanical loading system of the three-dimensional coal and gas outburst simulation experimental device. It is found that at present, the mechanical loading problem of the large-scale outburst model is mainly solved by two methods, that is, the distribution loading of multiple groups of hydraulic cylinders or by improving the rigidity of the mechanical loading system and the loading capacity of hydraulic cylinders; at the same time, the solid mechanics module of COMSOL simulation software is used to analyze the influence of different pressure plate structures (flat plate type and trapezoidal type) on the stress and deformation of outburst coal. The results show that the homogeneity of stress exerted by mechanical loading system on outburst coal can be improved relatively when trapezoidal structure plate is used.