Abstract: In this paper, the 0.36° high-phase-resolution space charge characteristics of polyimide in different aging states under bipolar square wave pulse electric field were detected. The space charge dynamic response of square wave electric field in the range of 1~100 kV/mm, frequency of 10 Hz~10 kHz and rising edge of 20 μs~10 ms is analyzed, and the effect of square wave pulse field parameters on the space charge transport in polyimide is discussed by combining the physicochemical and dielectric properties of polyimide before and after aging. The results show that, with the increase of the electric field amplitude, the mean phase charge density ρ_av increases and the maximum electric field distortion δ_max decreases, which may be related to the increase of the charge of the same polarity injected into the electrode at high field. With the increase of frequency, the charge accumulation ρ_av decreases, which may make it difficult to form effective charge accumulation due to rapid charge injection and withdrawal. With the increase of the rising edge time, ρ_av increases first and then decreases, which may be related to the effective duration of the electric field. The space charge accumulation in unaged polyimide samples is dominated by heteropolar charge, and the homopolar charge is increased significantly in the inner layer of samples near the lower electrode after aging. Combined with physicochemical properties, the molecular cleavage and other impurities contents are increased after aging polyimide, which may be related to the decrease of charge injection barrier.