Metal oxides with a polar surface interact strongly with polar NO 2 molecules, thus facilitating sensitive detection of NO 2 . In this work, the composites comprising graphene and cubic CeO 2 nanoparticles with the {100} polar surface are prepared by a hydrothermal technique, and they exhibit fast response, excellent selectivity, stable recovery, and sensitive detection with a low detection limitation of 1 ppm for NO 2 at room temperature. According to the first-principle calculations, the adsorption energy of NO 2 on the CeO 2 {100} polar surface is the most negative corresponding to the strongest interactions between them. The formation energy of oxygen vacancies (O v ) on the {100} polar plane is also negative, and the abundant O v facilitates the adsorption of NO 2 . The internal electric field near the polar surface promotes the charge separation and accelerates the charge exchange between NO 2 and the composites. In addition, graphene promotes electron transfer at the interface and improves the stability of the CeO 2 {100} polar surface. The composites of graphene and metal oxides with a polar surface are excellent for NO 2 detection, and the discovery reveals a new sensing strategy.