The fast fault clearing and recovery of high voltage direct current(HVDC)transmission line are very important for the stable and reliable operation of the entire power system. This paper analyzes and summarizes the existing clearing and recovery strategies of DC line faults in both line commutated converter based HVDC(LCC-HVDC)system and voltage sourced converter based HVDC(VSC-HVDC)system. It is pointed out that the blind recovery in existing strategies will make greater impact on the entire system or unnecessary outage. A possible solution is proposed that the adaptive recovery of DC line faults in different HVDC transmission systems should be studied to achieve the safe and rapid recovery of HVDC transmission system and improve the comprehensive processing method of DC line faults.