The invention relates to an MMC direct current short circuit breakdown detection method and apparatus. According to the invention, the method includes the following steps: dividing converter stations into a main station and sub-station modes, selecting one converter station as the main station and other converter stations as sub-stations, the main station gradually boosting a DC voltage, the sub-stations tracking the DC voltage of the main station through the difference between a DC current feedback value and a DC current reference value, and if the time duration when DC voltage that is boosted by the main station is constantly smaller than a first set value is set as T1, determining that the DC short circuit breakdown is still on. According to the invention, communication among stations is not required in the entire breakdown detection process, no other detection devices are needed, and the short circuit breakdown detection is realized by means of original DC voltage and current sensors, which provides reliable guarantee for boosting the DC voltage if the DC short circuit breakdown is not completely cleared, and secondary short circuit, sub-module fast discharging and being bypassed, and lockout and tripper of converters.