The invention belongs to the technical field of chemical industry, smelting industry and coal industry, and particularly relates to a novel underflow anti-clogging discharge method and a novel underflow anti-clogging discharge device, which are created and modified on the basis of a conventional thickener underflow discharge system, for a thickener. In order to solve the current situation that potential safety and environment-friendly hazards such as pipeline clogging, pump body coagulation, underflow overflow and the like are liable to occur in a natural underflow discharge process of the thickener, and the maintenance cost is high, the invention provides a safe, environment-friendly and efficient underflow anti-clogging discharge method and underflow anti-clogging discharge device for the thickener. The novel underflow anti-clogging discharge method and the novel underflow anti-clogging discharge device have the characteristics of being anti-clogging, safe, environment-friendly, convenient and time-saving to repair and maintain, capable of reducing the maintenance cost, stable in underflow discharge, and high in efficiency.