Throughaseriesofmodeltests,thewaveforcesonhorizontalandinclinedcircularcylindersaremeasuredandanalyzed.BasedonMorisonEquationandStokessecondorderwavetheory,therelationshipbetweenthehydrodynamicforcecoefficientswithKCnumberandsub-mergedwaterdepthaswellforhorizontalcylindersareanalyzed,alsotherelationshipbetweenthehydrodynamicforcecoefficientswithKCnumber,inclinedangleandtheeffectofwaterfreesurfaceaswellfortheinclinedcylindersareinvestigated.