The invention relates to the technical field of circuit protection, and more specifically relates to an adaptive discrimination method for the zero-sequence protection direction of a distribution line. The adaptive discrimination method comprises the steps of inputting a CT polarity automatic detection function when the distribution line is put into operation with load, comparing the phase difference between phase current Ip and phase voltage Up of a three-phase CT, carrying out comparison with a manually set load current direction, judging the polarity of the CT, automatically reversing the polarity of the three-phase CT if the polarity of the CT is reversed, quitting the CT polarity automatic detection function and the load current direction after the line is put into operation; comparing the phase difference between self-generating zero-sequence voltage 3U0 and self-generating zero-sequence current 3I0 when a grounding fault occurs in the line, and discriminating the zero-sequence protection direction according to the phase difference. The adaptive discrimination method can avoid a problem of low zero-sequence current measurement accuracy caused by a too small secondary value ofthe self-generating zero-sequence current. The zero-sequence protection direction discrimination adopts the self-generating zero-sequence current and self-generating zero-sequence voltage, and the three-phase CT has already verifies the polarity when being loaded, thereby effectively avoiding the risk of failure to operate due to the reversed polarity connection of the zero-sequence CT.