Abstract: The invention relates to a self-adaptive positive-sequence current quick-break protection method for a petal-shaped power distribution network trunk line. The method comprises the following steps: step 1, calculating a positive-sequence voltage phasor and a positive-sequence current amplitude at a protection installation position when a fault occurs, acquiring and storing a positive sequence impedance value of a protected line; judging a fault type, and judging a fault direction; step 2, when a fault direction element judges that a fault occurs in the forward direction, selecting a self-adaptive current quick-break protection setting formula according to the fault type, and when positive sequence current measured by protection is larger than a protection setting value, judging that the protected line has a short-circuit fault, and making a circuit breaker trip quickly.