A calibration method for the installation pose of a line laser sensor suitable for serial-parallel machine tools is proposed to address the challenge of accurate pose calibration. Based on the characteristics of standard spheres to calculate the spherical center coordinates, an equation was established using the invariance of the sphere center, and a target function for calculating the rotation matrix was proposed. Point cloud data from the surface of the standard sphere was scanned, and the spherical center was fitted. A model for computing the translation matrix was developed by comparing the fitted center with the true center coordinates. Compared with a traditional hand-eye calibration method, the calibration errors of the proposed method in the X, Y, and Z directions have been reduced by 88.9%, 83.6%, and 82.1%, respectively. This method eliminates the need to alter the pose of the serial-parallel mechanism, effectively mitigating the impact of positioning errors on pose calibration, thus significantly enhancing calibration accuracy.