The invention provides a system for discharging liquefaction residuals produced by direct coal liquefaction, a breakdown maintenance method and application thereof. The system for discharging coal liquefaction residuals comprises a decompression tower, a vacuum system, a main pipeline for discharging liquefaction residuals and at least one forming machine, wherein the main pipeline for discharging the liquefaction residuals is arranged at the bottom of the decompression tower and consists of a small circulating main pipeline and a large circulating main pipeline; both the small circulating main pipeline and the large circulating main pipeline of the main pipeline for discharging the liquefaction residuals are provided with main pipeline jackets; the front ends of the small and the large circulating main pipelines are jointly provided with a tower bottom discharging valve V0, a pump inlet cut-off valve V1 and a residuum pump P1 at the bottom of the decompression tower; the back ends ofthe small and the large circulating main pipelines are jointly provided with a liquid level control valve V5; and a branch-pipeline emergency cut-off valve V6, a ball valve V7 and a remote control adjusting valve V8 are connected between each branch pipeline and each forming machine. When the system and method for discharging coal-to-liquids residuals are used for maintaining a blocked branch pipeline or a branch pipeline in which a valve bank fails, other branch pipelines can run normally, and the running of the entire device is not influenced.