The dynamic response study of explosion venting components is of great significance for the assessment of explosion disasters and the determination of damage. Based on the self-developed rectangular explosion venting device, a series of experimental investigations on the dynamic response and failure mode of calcium silicate vent plates under the methane explosion loads induced by a detonator were conducted. The results show that the vent plate mainly exhibits brittleness and presents a plastic hinge failure mode under the blasting loads. When the gas concentration is closer to the stoichiometric concentration, P2 (the peak overpressure generated by the vent plate rupture) and its pressure rise rate dP2/dt are higher. Conversely, when the methane concentration is closer to the upper or lower limits of the explosion, the explosion load tends to be static, the yield line of the vent plate is shorter, and there are fewer fragments generated by the failure of the plate. The pressure-displacement curve and the correlation diagram of failure modes proposed provide a reference for predicting the failure mode of light and fragile explosion venting components.