The invention relates to the power distribution line technology field, and especially relates to a power distribution automation FTU latch-up protection method. An FTU closed locking fixed value on amain line of a power distribution network is set according to the number of times of instantaneous faults which occur within a certain period of time; then, each FTU closed locking fixed value on themain line of a power distribution network is set according to n times/X minutes, n+2 times/X minutes, n+4 times/X minutes and the like from a load side to a power supply side, and a fixed value n canbe set according to field experience and is generally 3. When the instantaneous fault occurs, each section switch FTU flowing through a fault current starts counting and counts tripping times, and other section switches which do not satisfy a condition only trip and do not start functions of counting and counting the tripping times. The method has no influence on permanent faults and the instantaneous faults, frequent tripping of a switch can be effectively avoided for the frequent instantaneous faults in a short time, a damage to primary equipment is prevented, and electricity experience of acustomer is improved.