简介：Followingclassicaltheory,atwo-layerfrontalmodelisdesigned.Itassumesthatfrontalsurfaceisthezero-orderdiscontinuityofdensity.Inthispaper,themodelisusedtostudyorographicallydistortedandoccludedfronts.Itisindi-catedthatthedistortionandocclusionofcoldfrontsaredifferentunderdifferentconditionsoforography.Frontalin-tensityalsoinfluencesthedistortionandocclusion.Somerulesarerevealedandcomparedwithobservations.Inaddition,wehaveanalysedtheverticalstructureofcoldfrontabovemountainsandfoundthatfrontalsurfacemaybebulgedundertheinfluenceoforographywhenitclimesthemountain.ThebulgeoffrontalsurfaceisjustliketheboreaspointedoutbyLong(1972)whenheanalysedfluidoverobstacles.