A　time-domain　method　is　proposed　to　compute　the　hydrodynamic　pressure　on　the　deep-water　cylindrical　structure　of　large　diameter.　In　the　computation　of　the　hydrodynamic　pressure　on　the　deep-water　cylindrical　structure　of　large　diameter,　the　water　should　be　compressible.　The　frequency-domain　hydrodynamic　pressure　formulation　is　derived　by　the　analytical　method.　This　formulation　has　the　high　costs　of　computation　and　storage　in　time-domain　analysis　due　to　the　Fast　Fourier　Transform　or　temporal　convolution　computation.　Using　the　convolution　algorithm　consisting　of　the　frequency-domain　rational　function　approximation　and　time-domain　auxiliary　variable　realization,　the　frequency-domain　hydrodynamic　pressure　formulation　is　transformed　into　an　accurate　and　efficient　method　in　time　domain.　The　numerical　example　indicates　the　effectiveness　of　the　proposed　method.