The invention discloses an electrical discharge wire cutting machining discharge state detection device, which comprises a current sensor, a voltage division circuit, a comparison circuit, a signal driving circuit and a floating voltage stabilizing power supply circuit; the detection device controls the three discharge states of no-load, spark and short-circuit during the processing process by the on-line real-time sampling of the duty ratio of the gap voltage waveform and the on-line real-time adjustment of the output voltage of an adjustable voltage stabilizing power supply; the floating on-line real-time detection is carried out by the respective lasting times of the no-load, the spark and the short-circuit in the single pulse width and the relative time utilization ratio, which can effectively solve the problem that the gap voltage is fluctuated along with the gap current and further improve the detection precision and the sensitivity of the discharge states of the no-load, the spark and the short-circuit.