Buried　pipes　are　widely　used　for　submarine　water　transportation,　but　the　complex　operating　conditions　in　the　seabed　pose　challenges　for　the　modeling　of　buried　pipes.　In　order　to　more　accurately　capture　the　dynamic　behavior　of　the　buried　pipes　in　the　seabed,　in　this　study,　considering　the　pipeline　and　soil　as　a　systematic　structure　is　proposed,　improving　the　fluid-structure　interaction　four-equation　model　to　make　it　applicable　for　the　calculation　of　buried　pipe　system　modes.　After　verifying　the　practicality　of　the　model,　considering　the　external　seawater　as　uniform　pressure,　the　coupling　at　the　joints,　and　the　Poisson　coupling　of　submarine　pipelines　during　transient　processes　are　discussed,　revealing　that　structural　vibrations　under　both　forms　of　coupling　will　cause　greater　hydraulic　oscillations.　The　impact　of　soil　elastic　modulus　on　the　system＇s　response　is　further　discussed,　revealing　that　increasing　the　modulus　from　0　to　1015　Pa　raises　the　wave　speed　from　498　m/s　to　1483　m/s,　causing　a　40%　increase　in　the　amplitude　of　pressure　oscillations.　Finally,　the　vibration　modes　of　the　combined　structure　of　pipe　wall　and　soil　are　discussed,　revealing　that　the　vibration　modes　are　mainly　dominated　by　water　hammer　pressure,　with　the　superposition　of　pipeline　stress　waves　and　soil　stress　waves.　In　this　study,　the　dynamic　behavior　of　submarine　pipelines　is　elucidated,　providing　a　robust　foundation　for　regulating　and　mitigating　fatigue　failures　in　such　systems.