NOVELTY - A sewage degradation continuous flow reactor comprises mud reduction reactor sequentially connected with microorganism continuous flow reactor and two sedimentation tanks via second and third water inlets; air inlet separately opened above the mud reduction reactor and microorganism continuous flow reactor; aeration device separately installed beneath the inside part of mud reduction reactor and microorganism continuous flow reactor; mud return pipe, water outlets and first water inlet; and elastic material distributed in mud reduction reactor and provided with Naididae.    USE - A sewage degradation continuous flow reactor for Naididae-microorganism symbiotic system used in synchronous treatment of sewage and mud (claimed).    ADVANTAGE - The processed sewage reaches standard B level one in terms of Standard on Pollutant Emission of City Sewage Treatment Works. The mud reduction rate is more than 60%.    DETAILED DESCRIPTION - A sewage degradation continuous flow reactor comprises mud reduction reactor sequentially connected with microorganism continuous flow reactor and two sedimentation tanks via second and third water inlets; air inlet separately opened above the mud reduction reactor and microorganism continuous flow reactor; aeration device separately installed beneath the inside part of mud reduction reactor and microorganism continuous flow reactor; mud return pipe connected with mud reduction reactor, microorganism continuous flow reactor and sedimentation tanks; water outlets arranged on upper sections of sedimentation tanks; first water inlet installed on upper section of mud decrement reactor; and elastic material distributed in mud reduction reactor and provided with Naididae. The active mud with microorganism is positioned in microorganism continuous flow reactor. An INDEPENDENT CLAIM is included for method of using sewage degradation continuous flow reactor, comprising feeding mud-containing sewage into mud reduction reactor via first water inlet; passing muddy solution in microorganism continuous flow reactor through solution return pipe; constantly feeding residual mud in two sedimentation tanks into mud reduction reactor via mud return pipe, where mud in mud reduction reactor is eaten and degraded by Naididae; flowing sewage with reduced mud into microorganism continuous flow reactor via second water inlet, where microorganism degrades organic pollutant, nitrogen and phosphorus in sewage, and some solution returns to mud reduction reactor; and feeding solution in continuous flow reactor into two sedimentation tanks via third water inlet, where precipitated mud returns to mud reduction reactor and standardized water is discharged from water outlet. The consistency of dissolved oxygen in microorganism continuous flow reactor is controlled at 2-3 mg/L.