Three　axisymmetric　2D　numerical　model　including　a　spherical　and　two　cylindrical　constant　volume　combustion　vessel　with　different　diameter　to　length　ratio　are　constructed　to　explore　the　geometric　effects　and　possibility　of　adopting　cylindrical　vessel　in　measurement　of　laminar　burning　velocity　(LBV)　by　constant　volume　method　(CVM).　Two　methods　are　adopted.　First,　the　exact　combustion　properties　from　simulation　are　used　to　extract　the　LBV.　Second,　the　estimated　combustion　properties　based　on　the　experimental　techniques　are　applied.　The　results　show　that　the　combustion　pressure　and　pressure　rise　rate　are　almost　same　in　three　different　chambers　before　flame　touching　the　wall,　but　in　cylindrical　vessel,　flame　surface　area　is　changed　by　cylindrical　confinement.　The　violation　of　spherical　flame　assumption　applied　in　CVM　results　in　the　obvious　overestimation　of　LBV.　However,　the　discrepancy　of　LBV　is　not　shown　when　the　estimated　combustion　properties　commonly　adopted　in　practice　are　used,　because　the　simplified　properties　do　not　capture　the　true　burned　mass　fraction.　Therefore,　the　pressure　data　before　flame　hitting　the　chamber　wall　in　cylindrical　vessel　could　perform　same　accuracy　with　that　of　spherical　vessel　in　experiment.　The　flame　impacting　timing　could　be　easily　identified　by　the　sudden　drop　of　pressure　rise　rate.　The　only　concern　is　that　the　final　pressure　used　in　calculating　the　burned　mass　fraction　may　be　reduced　by　heat　loss　in　cylinder　vessel.　It　is　suggested　that　before　the　pressure　date　in　cylindrical　vessel　is　utilized　in　determination　of　LBV,　the　final　combustion　pressure　obtained　in　cylindrical　vessel　should　be　compared　with　the　data　in　spherical　vessel,　at　least　compared　with　ideal　constant　volume　equilibrium　pressure　to　evaluate　the　deviation.