In view of the random error caused by the vibration of synchronous motor when detecting the section distance of a laser displacement sensor, position sensitive device (PSD) photoelectric displacement sensor and raspberry are used to collect the error data. Taking the barrel equipment in the laboratory as an example, the curve fitting is carried out with Python, MATLAB and other software, and the collection and analysis of barrel data error are described. The basic flow of processing and curve fitting is analyzed, and the application of PSD in position error compensation is discussed. The barrel detection based on laser displacement sensor improves the reliability of detection data, reduces the error caused by vibration, and lays a foundation for subsequent data acquisition, processing and three-dimensional reconstruction.