The invention belongs to the technical field of thermal battery testing, and particularly relates to a thermal battery single battery testing device and a thermal battery single battery testing method. The device comprises a single battery assembling system and a single battery electrical property testing system, the single battery assembly system comprises a first stainless steel bracket, a motor, an upper pressure plate, an upper insulating sheet, an upper current collecting sheet, a second stainless steel bracket, a material pushing and returning device, a single battery, an anti-overflow ring, a stainless steel sheet, a lower current collecting sheet, a lower insulating sheet, a lower pressure plate, a pressure sensor and a heating furnace. A single battery assembly system does not need to be repeatedly assembled during each test such that the assembly and test difficulty of the single battery is greatly simplified, and the consistency of test conditions of the single battery is ensured; the constant-temperature system and the constant-pressure system are separately arranged such that the heating device cannot be damaged under high pressure, and the respective working stabilityof the two systems is guaranteed.