Analytical　methods　are　developed　to　investigate　the　interaction　of　water　with　multiple　cylinders　with　arbitrary　smooth　cross-sections　subjected　to　horizontal　ground　motion　and　incident　linear　waves.　Based　on　the　boundary　conditions　of　the　seafloor　and　the　water　surface,　the　three-dimensional　Laplace　equation　was　transformed　into　the　two-dimensional　(2D)　Helmholtz　equation.　Based　on　the　condition　that　the　coefficient　function　of　the　cyl-inder　surface　can　be　expanded　into　a　Fourier　series,　radiation　theory　and　diffraction　theory　are　extended　to　solve　earthquake-induced　hydrodynamic　forces　and　wave　forces　on　multiple　cylinders.　The　proposed　analytical　so-lution　consists　of　the　high-order　scattered　wave　pressures　due　to　diffracted　waves.　The　present　method　was　verified　using　two　double　cylinder　arrays　with　elliptical　and　round-ended　cross-sections.　Finally,　this　method　was　extended　to　multiple　scattering　analysis　for　the　interaction　of　water　under　earthquake　and　wave　loads.