In order to characterize the microstructure and properties of matrix of porous carbon foam, phenolic-based carbon were synthesized by curing and carbonization of base-catalysis thermo-setting phenolic resin. Microstructure, compressive properties and fracture toughness of syntactic phenolic-based carbon were studied. The results showed that phenolic-based carbon mainly contained three phased: resin-derived carbon, micropores and microcracks; and carbon element existed in the form of sp₃-rich amorphous carbon. The compressive strength of phenolic-based carbon is 8.58 MPa, whose compressive fracture characteristic is brittle fracture. Its fracture toughness is worse, which was marked by the energy in compressive fracture of 0.135 MJ.m_-3.