Abstract: In order to solve the difficult problem of borehole trajectory measurement under the condition of screen pipe lowering technology in soft coal seam, the drilling track measurement equipment and technology under screen pipe lowering condition were studied. A small probe tube for track measurement used in screen tube and a hand-held control terminal are designed and developed. The probe tube is connected with the handheld control terminal through Bluetooth. After the formation of the borehole, a pusher is used to send the probe pipe into the borehole passing through the screen pipe for trajectory measurement, which solves the problem that the borehole trajectory measurement cannot be carried out after the screen pipe is lowered. The field test results show that the measurement system has high reliability and accurate data.