In order to improve the quality of reclaimed water, a coupling process with solid carbon source of corncob cellulose and sulfur/sponge iron composite fillers was integrated for the further deep removal of nitrogen and phosphorus for municipal wastewater treatment plant (WWTP) effluent that usually contains little organic carbon for heterotrophic denitrifying bacteria to utilize. Based on the bacteria 16S rRNA gene clone library analysis by adopting the high-throughput sequencing technologies, both the effect and mechanism of the system (abbreviated as SCSC-S/Fe) on nitrogen (N) and phosphorus (P) simultaneous removal from simulated WWTP effluent were investigated. The results indicated that the TN removal efficiency of the system increased gradually with the increase of temperature, but the removal rate of TP did not raised obviously. Under the condition of 30℃temperature and 9h HRT, the average removal rates of NO₃^--N, TN and TP were 99.86%, 92.70% and 89.15%, respectively. There were two main classes of bacteria including cellulose degradation and denitrification bacteria with the total bacteria of 41.37% and 54.02% separately in the solid carbon source of corncob cellulose unit. And there were simultaneous existence of heterotrophic, hydrogen and sulfur autotrophic denitrifying bacteria accounted for 91.53% of the total number of bacteria in the sulfur/sponge iron composite fillers unit. X-ray diffraction (XRD) analysis showed that PO₄^3- was removed mainly by the form of FePO₄, Fe₃(PO₄)₂·χH₂O and Fe₃ (PO₄)₃(OH)₂. In the system, the nitrogen was removed mainly by heterotrophic denitrification with auxiliary hydrogen and sulfur autotrophic denitrification, and the phosphorus was removed by main chemical reaction and a little biological uptake of phosphate. SCSC-S/Fe system represents a promising method for simultaneous and improved N and P removal from WWTP effluent.