An active probe and a method for measuring space charge distribution of polymer are provided. The active probe includes a case, electric pulse transmission unit, piezoelectric ceramic sheet, quartz glass block and signal-extracting aluminum block. An outer surface of the quartz glass block is adhered with a conductive material in contact with the case. An anode of the piezoelectric ceramic sheet is connected to the electric pulse transmission unit, and a cathode of the piezoelectric ceramic sheet is connected to the conductive material on the outer surface of the quartz glass block. The signal-extracting aluminum block is respectively connected with the quartz glass block and the measured signal extraction unit.