The invention provides a thermocouple pre-embedded thermal insulation coating test-piece interface temperature testing method. by a method of firstly pre-embedding a thermocouple measuring point on the shell surface and then spraying a thermal insulation coating, accuracy of interface temperature testing results is raised, and accurate test basis is provided for the coating thickness design. Geometric size of a test-piece and geometric size of the used thermocouple, mainly diameter parameter and geometric size of the measuring point, should be as small as possible, thus reducing influence of geometric size of test equipment on test results of the test-piece at the greatest extent; the measuring point is positioned close to the middle part of the test-piece, so as to minimize influence of the boundary effect on test results; the thermocouple is positioned inside a preset groove to guarantee thickness of the sprayed coating, and simultaneously an adhesive for fixing the thermocouple is used to reduce influence on test results from the aspect of geometric size; and two measuring points are usually used so as to check the consistency of test results. The thermocouple measuring points are arranged on the interface for direct measurement so as to guarantee that test results are direct and accurate.