In order to simulate the rockburst induced by the horst combination fault instability and to obtain the analytical solution for the roof equilibrium structure in the horst combination fault influence areas, the roof is simplified into a shear beam model. Based on the elastic shear beam model, the position of the maximum equivalent shear in the roof is determined and the computational formula for the roof's first caving step is obtained. The roof equivalent shear increases with the increase of the span of the gob.The first weighting takes place when the equivalent shear reaches the top limit, and the roof fracture location appears in the interior of the coal seam. The first weighting and the periodical weighting of the roof in the stope are analyzed. In the stope, horst faults are found. And the elastic-plastic shear beam model is used in the analysis. which shows that horst faults may exist in the stope.The faults will slip, the energy will be released and the mine tremor will occur, when the maximum equivalent shear reaches the shear limit of the faults.