The invention discloses a delay measurement method, device and system for a direct current transmission system. According to the topology of the direct current transmission system, the delay of the whole link is divided into four parts of delay of an IO interface link, delay of a pole control link, delay of a valve control link and delay of a submodule execution link. The delay of the link of eachpart starts from reception of a signal until the signal is sent to a subordinate system, the delay of the link of each part can be independently tested, a start signal and an end signal of the time delay test are both connected into the delay measurement device, and the consistency of measurement is ensured. The delay of the overall and partial links of the direct current transmission system is tested to play an important role in the optimization of the subsequent delay and the compensation of control.