The invention discloses a direct current power transmission converter valve-based electronic device and system, wherein the device comprises at least one trigger monitoring plate, at least one main control panel and at least one thyristor trigger monitoring board card; the trigger monitoring board comprises at least one optical fiber transceiving interface, wherein the optical fiber transceiving interface is connected with the thyristor trigger monitoring board card and is used for achieving bidirectional communication with the thyristor trigger monitoring board card and realizing informationtransmission; the thyristor trigger monitoring board card is used for detecting the resistance and/or capacitance parameter information of a thyristor level of a tested circuit, the turn-off angle information of the thyristor level of the tested circuit and phase change failure state information; and the master control panel is used for recording and transmitting the information. By implementing the device, the occurrence of phase change failure can be prevented by acquiring the parameter information of a circuit element, so that the overhaul capability of the converter valve is improved.