The invention discloses a portable impact current generator for measuring the impact ground resistance. The portable impact current generator comprises a main circuit and a control circuit. The main circuit is used for generating an impact current and is connected with the control circuit. The control circuit is used for controlling the main circuit to conduct the pulse discharge. The tail end of the main circuit is respectively connected with the current injection electrode and the backflow electrode of a grounding body. The current injection electrode is connected with a pulse voltage divider. The measuring end of pulse voltage divider is connected with an oscilloscope. The portable impact current generator further comprises a rogowski coil connected in series with the backflow electrode. The rogowski coil is connected with the oscilloscope. According to the technical scheme of the invention, the current impact of the grounding body is measured, and measured impact voltage and current waveforms are accurate and reliable. Meanwhile, the portable impact current generator is small in size, light in weight, convenient to transport and assemble, low in test cost, and simple and convenient to operate. The test dangerousness is greatly reduced. Meanwhile, the charging voltage can be up to 50 kV and the amplitude value of the impact current can be up to 3kA.