The geological conditions of the slopes on both sides of the reservoir area of the hydropower station are complex and changeable. The stable working condition of the slopes is closely related to the safe operation of the hydropower station. In this paper, the MEMS attitude sensors (gyroscopes and accelerometers) are arranged on the slopes by the array mode at the left slope cover layer of the reservoir area of the Yalong River Guandi Hydropower Station. Using the initial alignment, a real-time slope stability data acquisition system is established to determine the navigation target parameters′ attitude, orientation, velocity and position. The initial values of philosophy, bearing, speed and position are calculated. Then the acceleration and angular momentum under the load system acquired by the MEMS attitude sensors are converted to the navigation system in real-time through the attitude matrix, which is used to calculate the slope change attitude matrix and displacement in real time to carry out experimental research. The experimental results show that applying the MEMS attitude sensor to slope displacement monitoring can achieve real-time acquisition of slope surface displacement data. The displacement data acquisition accuracy can reach the millimetre level to meet the actual needs of engineering. The research results are of great significance to the real-time monitoring and analysis of the stable state of slope surface displacement.