A GNSS/IMU-based tilt measurement system includes a GNSS/IMU receiver. The GNSS/IMU receiver includes a GNSS antenna, a GNSS positioning board, an IMU inertial sensor and a position transfer device. The GNSS antenna is configured to receive a satellite navigation positioning signal. The GNSS positioning board is configured to calculate coordinates of the phase center of the GNSS antenna according to a signal received by the GNSS antenna and use the coordinates of the phase center as reference coordinates for measuring a relative position point. The IMU inertial sensor is configured to measure the acceleration and the angular velocity of the receiver. The relative position transfer medium is configured to connect the reference coordinates and the coordinates of the relative position point to be measured. The position transfer device is configured to implement the measurement function of the relative position point.