Abstract: The commutation failure is one of the common faults of the line commutated-converter based high voltage direct current（LCC-HVDC）. It is one of the research emphases in the development of China’s power grid to enhance the ability of HVDC system to mitigate the commutation failure. Firstly, the mechanism and influencing factors of commutation failure were analyzed. Then, from the detection and judgment of fault, the first commutation failure suppression, and the following commutation failure suppression, the suppression methods based on control protection were detailed combined and analyzed. Finally, commutation failure of many factors were dynamically coupled, the commutation process is highly discrete, following commutation failure generation mechanism is unknown, leading to inhibition of commutation failure protection policy exists to control blindness, hysteresis, subjectivity and other issues. Research on the coupling law of multi-influence factors and the continuous research of discretization commutation process and the following commutation failure based on control behaviors are the focus of future research on commutation failure suppression.