The invention discloses a long-distance underground passage wiring mechanism and a wiring method thereof. The long-distance underground passage wiring mechanism comprises two supporting plates for supporting a cable tray and a guide mechanism which is used for the two supporting plates to slide in a face-to-face manner, wherein two supporting plates are installed on the guide mechanism in parallel, and a distance between the two supporting plates is adjustable; and the long-distance underground passage wiring mechanism also comprises a cycloidal mechanism for pulling a cable to move towards two sides. The wiring method comprises the following steps: adjusting the distance between the supporting plates, enabling a length of the distance to be greater than the length of a middle shaft of the cable tray, moving the cable tray to be between the two supporting plates, raising the cable tray, enabling two ends of the middle shaft of the cable tray to be respectively aligned to a shaft hole on the supporting plate at the corresponding side, adjusting the supporting plates, enabling the two supporting plates to move in a face-to-face manner, keeping the shaft hole on the supporting plate to sleeve two ends of the middle shaft, pulling the cable on the cable tray to penetrate through the cycloidal mechanism, starting the cycloidal mechanism, swinging the cable to a target position, and beginning the wiring. The cable tray wiring of different spans is integrated, and the cable wiring trajectory can be changed according to the requirement.