The invention relates to a pre-discharge current detection device. Ten non-inductive resistors of same resistance and discharge tubes are connected in parallel; one end of each resistor is grounded directly; two output ends which are connected in parallel are connected with an oscilloscope through coaxial cables; the ten non-inductive resistors are symmetrically, coaxially and vertically arranged into a circle; the discharge tubes are vertically arranged in the center of the circle. As the ten non-inductive resistors are in coaxial and symmetric arrangement, initial pre-discharge current can uniformly flow through the ten non-inductive resistors, and current signals come into the oscilloscope through the coaxial cables, so that good current flowing capability and fidelity are achieved. As streaming is converted into main discharge, and when large current flows through a pulse current detection unit, generated instantaneous voltage is discharged into the ground through gas discharge tubes, a measurement instrument and a signal line are prevented from being damaged because of over-voltage. Due to the simple and small structure, the pulse current detection unit can be put into a gas discharge pressure container, and the measurement instrument and the signal line are prevented from interference of a stray magnetic field caused by impact current and the like.