The invention discloses a relay protection fault analysis method and device based on a vector graph. The method comprises the following steps: calling a recording file and a standard logic diagram corresponding to the recording file from a relay protection device; reading recording data of the recording file, and displaying a recording waveform diagram according to the recording data; loading the standard logic diagram corresponding to the recording file, and displaying the loaded standard logic diagram; dynamically deducing the standard logic diagram according to the recording data recorded by the recording waveform diagram, and acquiring a deduction result comprising a logic delay primitive and a return line primitive; when the deduction result accords with the recording data of the recording file, displaying the deduction result on a display screen. By using the method and the device, a dynamic deduction logic diagram with the logic delay primitive and the return line primitive can be formed.