The invention discloses a pulse gap detection circuit for PCD material electric spark discharging. The pulse gap detection circuit comprises a sampling module, a configuration module, a high speed comparing module and an output module, wherein the sampling module, the configuration module, the high speed comparing module and the output module are sequentially connected. The sampling module further comprises a first resistor and a second resistor which are connected in series. The end, opposite to the first resistor, of the second resistor serves as a sampling output end, and a first diode is located between a joint of the sampling output end and the second resistor and a grounding end. A second diode is located between the joint of the sampling output end and the second resistor and a power source end. The first diode is connected with a filtering capacitor in parallel, and the second diode is connected with a third resistor in parallel. A joint between the first diode and the grounding end serves as a joint where a high-voltage input end is connected between a positive electrode and an inductor, and the end, opposite to the second resistor, of the first resistor serves as a low-voltage input end to be connected to a negative electrode. By means of the pulse gap detection circuit, real-time detection for a single discharge pulse is achieved, the accuracy and the reliability for detecting the gap state are greatly improved, and small pulse width machining is carried out on PCD materials.