Dimethyl ether(DME) steam reforming (SR) could provide excellent reducing agent of H2 for NOx storage and reduction (NSR) technology to remove nitrogen oxide (NOx) emissions from DME engine. This paper studied the influence of DME reforming gas on the performance of NSR by using Pt/Co-BaO/Al2O3 as NSR catalyst and CNZ-1/HZSM-5/Ga2O3 as the catalyst of DME steam reforming. The experimental result shows that the NSR performance is improved evidently by using the DME reforming gas as reductant. The conversion efficiency could be raised by 11%. Although the water vapor has some inhibition effect on the NOx adsorption, it participates in DME reforming and could produce evident promotion on the NOx conversion rate of NSR.