Dynamical performance of pipes conveying fluid on board is of great importance to the reliability of machinery.The dynamic equation of a simply supported wet pipe conveying fluid is presented,taking structural damping of the pipe and viscidity of the fluid into consideration.And the equation is also solved by using Galerkin’s method.Modal identifications based on strain gauge test are carried out on both dry pipes(without fluid in it)and wet pipes(pipes conveying fluid).It is concluded from the comparison of the results that bothnatural frequency and the damping ratio decrease as the pipe filled with fluid,but the mode shapes vary little.Variation of equivalent damping factor is also tested.Experimental results reveal that the equivalent damping factor of fluid and the damping ratio depend greatly on the initial deformation,and fluid induced damping decreases the universal damping ratio of the pipes conveying fluid. Dynamical performance of pipes conveying fluid on board is of great importance to the reliability of machinery. The dynamic equation of a simply supported wet pipe conveying fluid is presented, taking structural damping of the pipe and viscidity of the fluid into consideration. And the equation is is also solved by using Galerkin’s method. Modal identifications based on strain gauge test are carried out on both dry pipes (without fluid in it) and wet pipes (pipes conveying fluid). It is concluded from the comparison of the results that both natural frequency and the damping ratio decrease as the pipe filled with fluid, but the mode shapes vary little. Variation of equivalent damping factor is also tested. Experimental results reveal that the equivalent damping factor of fluid and the damping ratio depend greatly on the initial deformation, and fluid induced damping decreases the universal damping ratio of the pipes conveying fluid.