The invention discloses a sensor positioning device. The device comprises a sliding positioning assembly, a stand column is mounted on a detection frame, the stand column is in sliding connection withthe sliding positioning assembly, a sensor is mounted on the sliding positioning assembly, the stand column is provided with a stand column positioning assembly, and the stand column positioning assembly comprises a base. A first groove is formed in the base, a positioning block is mounted in the first groove, the positioning block is connected with the stand column through a second fastening device, one side of the positioning block is provide with an ejecting block matched with the positioning block, a second groove is formed in one side of the base, one end of a third fastening device extends into the second groove, and a bearing is arranged between the third fastening device and the ejecting block. Due to the sliding positioning assembly of the sensor positioning device, the sensor can detect detection data of line limits of different heights, the stand column positioning assembly is arranged, accuracy of repeated positioning between the stand column and the detection frame is ensured, and the sliding positioning assembly and the stand column positioning assembly are convenient to dismount and splice.