The invention discloses a cable trough combination for a rail transit system, and aims to provide a cable trough combination which is sunproof, rainproof, good in heat-dissipating and waterproof effect, and convenient and fast to use, install and maintain and is used for the rail transit system. The cable trough combination is characterized by comprising multiple connected cable trough combination units, and each cable trough combination unit comprises multiple cable trough supports arranged at intervals and an inverted-U-shaped cable trough cover used for shielding the cable trough supports and provided with openings in the two ends, wherein the cable trough supports are located in the cable trough cover and connected with the cable trough cover, the weight and the size of an installed device in the first step are reduced, installation is more convenient and easy to adjust, the installation accuracy is greatly improved in a narrow space particularly, the probability of reinstallation caused by mismatching installation is reduced, the working efficiency is improved, and follow-up overhauling and maintaining are facilitated.