The invention belongs to electric power system transmission line relay protection field and relates to a method for judging failure property of single-phase self-adapting reclosing based on fault point voltage: real-timely acquiring the voltage and current value of every phase on one side of the transmission line; measuring failure distance; real-timely computing the current actual fault point voltage; finding out the sound phase current and fault phase voltage at the two ends of the line, then finding out the approximate open circuit voltage of the fault point and the set-pressure using the result of sound phase current and fault phase voltage and the result of failure distance measurement; comparing the fault point voltage with the set pressure, an instantaneous failure is judged if thefault point voltage value is persistently larger than the set pressure within the set time period after single phase tripping, and the protection sends out a reclosing order after certain time delay;a permanent failure is judged if the fault point voltage value is always smaller than the set pressure within the set time period, and the protection will not reclose after tripping off the three phase line. The invention can ensure the persistency and stability of system power supply and avoid the damage by single phase reclosing and permanent failure to electric equipment.