Marine　structures　and　the　seabed　are　subjected　to　all　kinds　of　marine　environmental　loadings　for　a　long　time,　especially　wave　and　current　loadings.　Most　previous　investigations　of　the　dynamic　response　of　marine　structures　and　the　seabed　have　only　considered　the　influence　of　wave　loading,　but　the　important　influence　of　current　was　ignored.　In　recent　years,　some　scholars　have　studied　the　dynamic　response　of　the　seabed　under　combined　wave　and　current　loadings,　but　relatively　few　studies　deal　with　liquefaction　analysis　under　the　combined　wave　and　current　loadings.　On　the　basis　of　the　poro-elastic　theory　by　Biot　and　combined　two-dimensional　non-linear　progressive　wave　and　uniform　current　theory,　an　accumulated　excess　pore-water　pressure　calculation　model　considering　the　effect　of　instantaneous　pore　pressure　on　accumulated　pore-water　pressure　is　proposed　in　this　paper.　The　seabed　response　of　instantaneous　pore　pressure　and　accumulated　pore-water　pressure　under　the　combined　wave　and　current　loadings　are　calculated　through　this　model.　The　effects　of　the　time,　current　velocity,　consolidation　coefficient,　the　relative　density　and　water　depth　on　excess　pore　pressure　are　discussed　in　detail;　furthermore　the　stability　of　the　seabed　is　evaluated　through　the　liquefaction　analysis.