The research on the operation and application of the moving bed biofilm reactor (MBBR) process system under low temperature conditions was systematically elaborated from the aspects of microbial community, carrier enhancement technology, and process combination and regulation. Low temperature was found to inhibit the activity of nitrifying bacteria, affecting the nitrogen removal efficiency of wastewater treatment. The MBBR system was demonstrated to enrich nitrifying bacteria through biofilm formation. Cold-adapted microbial acclimation technology was shown to enhance microbial activity under low temperature conditions, effectively improving the operational efficiency and stability of this system. The selection of carriers was proven to influence process performance. Magnetic carriers, hydrophilic modifications, and porous structures (e.g., PVA gel) were found to enhance biofilm formation, increase the enrichment of nitrifying bacteria, and improve the treatment efficiency of low temperature wastewater. Optimization of the MBBR process required regulation of aeration, carbon-to-nitrogen ratio (C/N), and hydraulic retention time (HRT). Under low temperatures, intermittent aeration, low C/N, and extended HRT were shown to enhance nitrification efficiency. Process combinations such as A/O-MBBR were demonstrated to strengthen the system’s resistance to shock loads. This study provides a reference for further research and application of the MBBR process.