Abstract: Aiming at the defects of phenolic foam, such as brittleness and low strength, three kinds of glass fiber reinforcement with different forms, i.e. short chopped glass fiber (SGF), glass fiber needle with phenolic resin impregnated and cured (GFN) and 3D spacer grille fabric with phenolic resin impregnated and cured, were adopted to reinforce phenolic foam. The effects of fiber content and length on the compressive property of phenolic foam were studied. The compressive and thermal insulation properties of phenolic foams reinforced by different glass fibers were compared. The results indicate that phenolic foam reinforced by 5% mass ratio of SGF with 3 mm length has the largest specific compressive strength, which increases by 21% than pure foam. Specific compressive strength of phenolic foam reinforced by 25% mass ratio of GFN with 5 mm length increases by 8%. Specific compressive strength of phenolic foam reinforced by 3D spacer grille fabric slightly reduces, while its compressive strength (0.239 MPa) meets the requirement of load-bearing phenolic foam. Compared with phenolic foam without fibers, the thermal conductivities of phenolic foams reinforced by SGF or GFN are a bit higher, but still meet the requirement of efficient thermal insulation materials, while the thermal conductivity of phenolic foams reinforced by 3D spacer grille fabric increases apparently.