In response to the issue of accuracy in measuring the elevation of spatial coordinate points relative to a reference point, a new combined elevation measurement method based on a physical horizontal reference plane was proposed. By utilising the concepts of laser triangulation and leveraging the geometric features of measuring light pathways, a high-precision elevation measurement system was built. This technique employed a physical horizontal reference. Within a Lambertian scattering light field, an analysis was done to determine the influence of tilt angle modifications on the centroid displacement of laser energy. An related error correction model was built, which permitted tilt angle error compensation for elevation data by the use of a tilt angle sensor. Additionally, an autonomously constructed calibration platform was deployed for verification studies targeted at calibrating the suggested elevation measuring system. The findings demonstrate that the proposed combined elevation measurement method achieves a repeatable measurement error within a fluctuation range of ±20 μm across a 500 mm measurement range. Compared to the measurement methodology of single laser displacement sensor, the combined elevation measurement method greatly reduces the fluctuation of measurement errors. It is capable of supporting precise measurements of spatial coordinate points in any orientation and effectively boosting the performance of laser displacement sensors in the area of elevation measurement, consequently giving more genuine and effective measurement results.