Abstract: Technical and economic advantages and disadvantages of different construction models for modular prefabricated cabin main substation and conventional main substation, Taking the actual engineering design of a 110 kV main substation in a certain rail transit as an example, a detailed comparative analysis was conducted on the technical advantages and disadvantages, construction period, land occupation, and investment differences of different construction modes of the main substation. The study showed that under different external civil engineering conditions, prefabricated cabins increased investment by about 6.07%, saved land by about 52%, and shortened construction period by about 26.9% compared to conventional main substations. Under the same external conditions of civil engineering, prefabricated cabins save about 13.39% of investment and about 20%～40% of land compared to conventional main substations.