Abstract: A highly fire-resistant phenolic foam core sandwich reinforced with fiberglass through the thickness Z-direction was prepared, and the effects of distribution density, height, arrangement manner of load-bearing pillars, fineness of stitches and number of stitched layers on its mechanical properties were investigated. The results indicate that the mechanical properties of the Z-direction reinforced foam core sandwich are much better than those of the unstitched foam core sandwich. The arrangement manner of load-bearing pillars has little effect on its mechanical properties under the condition of uniform distribution density of load-bearing pillars. The height, distribution density of load-bearing pillars, fineness of stitches and number of stitched layers have great effects on the mechanical properties of the Z-direction reinforced foam core sandwich.