The invention relates to a method for detecting thermal shock resistance of a porous ceramic. The method comprises the following steps: cutting and processing a porous ceramic to obtain a sample, wherein the sample has a width of 8+/-0.2mm, a thickness of 6+/-0.2mm, a length of more than or equal to 70mm, and the parallelism of an upper surface and a lower surface of less than 0.02mm, the size ofthe sample has universal applicability to materials with different structures, and the problem that the existing sample size has large deviation of test values for materials with different structurescan be solved; clamping the sample on a clamp of a testing machine; detecting the thermal shock resistance of the sample by a four-point bending method to obtain test data of the thermal shock resistance of the sample; repeating the steps and gradually increasing the thermal shock temperature until the bending strength in the measured test data falls beyond product requirements or is damaged to such an extent that a bending test is difficult to perform; and obtaining thermal shock resistance data of the porous ceramic according to the test data and the thermal shock temperature. The method isscientific, reasonable, simple, feasible, fast and effective, and low in cost.