Constant　Volume　Combustion　Bomb　(CVCB)　is　a　useful　experimental　system　in　the　internal　combustion　basic　research.　A　new　structure　of　CVCB　was　designed　in　this　paper.　Its　solid　model　and　finite　element　model　were　built　through　Pro-Engineer　and　ANSYS　software.　Then　the　strength　was　calculated　and　the　structure　was　optimized　to　get　the　smallest　volume　with　ANSYS.　According　to　the　optimization　results,　the　volume　decreased　50%.