Abstract: Finite volume method with fifth-order WENO/MWENO scheme is developed to simulate water hammer and fluid-structure interaction (FSI) in pipes. The unsteady friction is introduced into the water hammer and FSI governing equations, the radial deformation is considered in FSI model, fifth-order WENO/MWENO scheme is used to solve the equations. A triple virtual boundary method is proposed to deal with the boundary calculations, the method simplifies the calculation process and keep the precision of the boundary element in fifth-order; third-order Runge-Kutta method is adopted for time integration to maintain the calculation precision. The calculation results of the established models are compared with exact solutions, and the accuracy and efficiency of the fifth-order models are analyzed. Results show that the proposed models have high applicability, they can better simulate the water hammer and FSI pressures in pipes, and can effectively avoid numerical oscillation; compared with the second-order models, the fifth-order models have higher computational accuracy and efficiency.