The invention relates to an aerial insulation line partial discharge detection and positioning device and method. The device mainly comprises the following units: a transmitting end host used for generating transmitting end time synchronization pulses and recording all pulse waveforms in a sampling period; a reflection end host used for being triggered to generate a reflection end time synchronization pulse after receiving the pulses generated at a transmitting end and recording all pulse waveforms in the sampling period; a transmitting end pulse injection sensor and a reflection end pulse injection sensor which are used for injecting pulses to an aerial insulation line through the law of electromagnetic induction; and a transmitting end pulse detection sensor and a reflection end pulse detection sensor which are used for detecting pulse signals in the aerial insulation line. The transmitting end host comprises a high-voltage pulse generation unit, a filtering unit and a data acquisition unit. The reflection end host comprises a high-voltage pulse generation unit, a filtering unit, a data acquisition unit and a trigger delay unit. The device is small in size and light in weight, does not need to cut off a power supply line during measuring, is high in measurement accuracy, and can improve stability, reliability and safety of the aerial insulation line in a power distribution network greatly.