The pursuit of larger apertures and higher precision remains a central goal in developing submillimeter-wave telescopes. To construct large-aperture telescopes with high precision, segmented panels are commonly employed. The surface accuracy of a segmented mirror is determined by cumulative errors from its sub-mirrors, which include manufacturing errors and alignment errors (e.g., Piston and Tip-Tilt errors). These errors degrade the reflector’s precision, thereby reducing the antenna gain. Considering scenarios involving both individual sub-apertures and the complete set of sub-apertures, this study simulates the effects of sub-aperture manufacturing errors and alignment errors on the overall surface accuracy of the Leighton Chajnantor Telescope (LCT) using Zemax and PAOLA software. Considering individual sub-apertures simulation, the sub-apertures farther from the center have a weaker influence on the overall surface accuracy of the primary. Considering the simulation for the complete set of sub-apertures, individual errors exhibit a linear correlation with the resultant surface error, while combined errors follow a root-sum-square relationship. Results from both software tools align within 5% deviation, validating the simulation methodology. This analysis provides critical guidance for optimizing error distributions in segmented reflector construction.