Discharge system after sewage treatment

The invention provides a discharge system after sewage treatment. The system comprises a sewage treatment device, a discharge pipeline, a water seepage pit and a valve, the sewage treatment device is arranged on the ground surface, and a heat preservation mechanism is arranged in the sewage treatment device; the water seepage pit is arranged below the frozen soil layer; the drainage pipeline is buried in the bottom layer of the frozen soil layer and passes through the upper portion of the water seepage pit, the water inlet of the drainage pipeline is connected with the water outlet of the sewage treatment device through a connecting pipeline, the water outlet of the drainage pipeline is connected with an irrigation pipe network, and an overflow pipe with an upward opening is arranged on the pipe section, located above the water seepage pit, of the drainage pipeline; and the valve is arranged at the water outlet of the discharge pipeline and is used for opening and closing the water outlet of the discharge pip