The invention discloses a photoelectric millimeter wave three-coordinate searching and tracking device. The device comprises a photoelectric detection component (1), a millimeter wave distance measuring component (2), a servo mechanism (3) and a processing component (4). The photoelectric detection component (1) is switched to the searching or tracking mode to search or track the target. The millimeter wave distance measuring component (2) is used for determining the one-dimensional phase sweep angle in the pitch direction according to the target pitch angle given by the photoelectric detection component (1), pointing the radar beams to the angle direction and measuring the distance of the target and/or the radial speed. The photoelectric detection component (1) and the millimeter wave distance measuring component (2) are installed on the servo mechanism (3). The processing component (4) is used for processing the image information acquired by the photoelectric detection component (1),extracting the target angle position information and controlling the millimeter wave distance measuring component (2) to measure the distance and/or measure the radial speed of the target of which the angle position information is acquired.