The pulse current method for partial discharge detection is generally applied in type testing and other off-line tests of electrical equipment at delivery. After intensive analysis of the present situation and existing problems of partial discharge detection in switch cabinets, this paper designs the circuit principle and signal extraction method for partial discharge on-line detection based on a high Voltage Presence Indicating Systems (VPIS). It establishes a high voltage switch cabinet partial discharge on-line detection circuit based on the pulse current method and develops background software integrated with real-time monitoring, judging and analyzing functions. Furthermore, it carries out a real discharge simulation test on a real-type partial discharge defect simulation platform of a 10 kV switch cabinet and verifies the sensitivity and validity of the high-voltage switch cabinet partial discharge on-line monitoring device based on the pulse current method. The study presented in this paper is of great significance for switch cabinet maintenance and theoretical study on pulse current method on-line detection, and has provided a good implementation method for partial discharge on-line monitoring devices for 10 kV distribution network equipment. This work is supported by National Natural Science Foundation of China (No. 51477100) and Science and Technology Project of State Grid Corporation of China (No. 52020114026L).