Carbon‐based catalysts have made significant progress in hydrodeoxygenation (HDO) of biomass. Since the HDO reaction usually carried on surface of catalyst, the interaction of reactant with catalyst is closely related to the surface microenvironment of catalyst, which may further have an impact on catalytic performance. This review will discuss the relationship between surface microenvironment of carbon support and catalytic performance and mechanism of HDO reaction during biomass upgrading. We will focus on the microenvironment effect associated with HDO reaction in carbon‐based catalysts including effects of surface microstructure and surface functionalization of carbon supports on preparation of heterogeneous catalysts and catalytic performance, respectively. Study of microenvironment may provide guidance for further development of efficient carbon‐based catalysts in biomass resource utilization.