Abstract: Carbon foams with high mechanical strength were prepared by polymerization of arylacetylene using sulfuric acid as a catalyst, pentane as a blowing agent and Tween 80 as a bubble stabilizer, followed by carbonization. Through controlling the preparation conditions such as the proportion of blowing agent, the concentration and volume of the catalyst, and the amount of the bubble stabilizer, carbon foams with good porous structure, smooth ligaments, and junctions without microcracks could be fabricated. The representative carbon foam possesses a high compressive strength of 25.8 MPa and a high strength/density ratio of 43.0 MPa/(g · cm^-3), owing to a high char yield of the arylacetylene polymer, which is up to 86% after carbonization, and a good pore structure of the products.