Abstract: In view of the lack of effective detection means in the automatic raising of coal mining machine,this paper analyzed the structure and the working principle of the shearer arm and then proposed a rocker angle measurement method suitable for the actual working condition for shearers and designed the angle sensor based on Giant Magneto Resistance effect. The sensor acquires the rocker arm position by installing a rocker-rotating mechanical component at the rocker pin shaft, and converts the swing into a magnetic field rotary motion. The integrated giant magneto resistance (IGMR) chip TLE5012B is used as the magnetic induction component, and the single chip microcomputer STM32F103C8T6 as the core control unit to fulfill functions such as the acquisition, conversion, processing, display, WiFi and RS485 transmission of angle signals. The test results show that the rocker angle sensor based on giant magneto resistance has a good linear relationship in the rocker swing range of the shearer, the non-linearity is 0.13%, the maximum absolute error is 0.23°, and the maximum relative error is 0.20%, which enables higher precision angle measurement.