In the manufacturing of ultra-precision optical elements, high-precision optical detection technology is the key to further improve the optical processing accuracy and to characterize and evaluate the optical surface morphology. Non-contact optical detection method has been widely used because of its high efficiency and no damage detection. But the external environment disturbance can easily affect the optical probe and reduce the detection accuracy. Therefore, a method of discrete detection path and splicing is proposed in this paper. The traditional spiral path is divided into multi-circular and multi-path paths. The compensation of environmental disturbance error is realized by the data splicing between paths. The parameter setting of discrete detection path is analyzed, and a uniform distribution strategy of circular path is given. Finally, based on the optical detection platform, the verification experiment of the compensation method of environmental error is carried out. Compared with the uncompensated results, the measurement relative error is reduced from 24.3% to 4.3%.