The present invention relates to a power distribution network failure removal accelerating method and a relay protection device. Removal acceleration of two-phase short-circuit and two-phase short-circuit ground faults is realized through non-channel acceleration protection. Each circuit breaker is at least equipped with two sets of protection, i.e., a first set of protection and a second set of protection, and accelerated judgments of the first set of protection and the second set of protection are also configured. The two sets of protection set according to respective time setting rules, each set of protection also sets according to corresponding accelerated judgment, and accelerated judgment setting time is a delay [delta]t of side breaker action time. When failures occur, for any breaker, if action conditions and the accelerated judgment of one of the sets of protection are met, whether to act is determined according to the setting time. When two-phase short-circuit failures and two-phase short-circuit ground failures occur, isolation of fault regions may be accelerated. For feeder lines with more and more subsections, a protection acceleration effect becomes more and more obvious.