Relying on the Integrated Modular Self-reflow Moving Bed Biofilm Reactor (IMS-MBBR), this article elaborates on the operational effect of this device in a rural domestic sewage treatment plant, combined with actual operating conditions. After 90 days of operation, the results show that the device is simple to operate, stable in operation, and effective in treatment. Under the impact of low-temperature conditions and mutations in water quality and quantity, the average effluent concentrations of COD, total nitrogen, ammonia nitrogen, and total phosphorus are 24.58 mg/L, 10.92 mg/L, 2.49 mg/L, and 0.26 mg/L, respectively, with stable effluent quality reaching Class 1A standards. Meanwhile, the device adopts a prefabricated reinforced concrete construction method, which effectively shortens the construction period and enhances the service life. The innovative integrated layout and pipeline design greatly reduce the number of equipment, enhance the stability and operability of the device, and lower the operation and maintenance costs. Overall, the IMS-MBBR facility provides a new solution for subsequent rural sewage treatment.