A sol-gel method has been utilized for synthesizing the wormhole-like mesoporous carbon (WMC), in which the gel skeleton can be regulated by using hydrofluoric acid and sulfuric acid. The electromagnetic characteristics of a series of WMCs with different surface areas embedded in paraffin at 15 wt% loading at 2-18 GHz were investigated. The electric conductivity of WMCs gradually increases with the decrease of surface area, leading to an increase in complex permittivity through dielectric loss. A minimum reflection loss (RL) value of -68.41 dB and a broader absorption band (reach 9.8 GHz) with RL values less than -10 dB are obtained, due to WMC's well matching the characteristic impedance and dielectric loss, implying its great potential as a microwave absorbing material.