The invention discloses an MMC power module protection thyristor breakover voltage test method. The test method is carried out by adopting a protection thyristor breakover voltage test device, and theprotection thyristor breakover voltage test device comprises a DC power supply S, a heating clamp, an ammeter and a voltmeter. According to the method, actual operation conditions of protection thyristors in an out-of-control half-bridge power module and an out-of-control full-bridge power module are simulated respectively, the breakover voltage of the thyristors can be accurately tested such that the thyristors suitable for the power modules can be more accurately screened, the loss of damage to the power modules caused by breakdown of an IGBT element is reduced, the probability that a wholeconverter is forced to stop running is reduced, and the reliability of system operation is improved.