Abstract: To realize the accurate control of water hammer process in pipes by valve stroking, it is important to obtain the analytical solution of the wave process of water hammer. Based on the analysis of the basic differential equations and the initial and boundary conditions of water hammer, traveling wave solution in finite domain is applied to the linear water hammer. Giving the velocity change relationship at the valve and using the theorem of integral curve independent of path, the accurate analytical solution of the dimensionless pressure is obtained in the valve closing process. Through solving extremum of the functionals by Ritz method, the rule of the velocity change and the corresponding rule of valve closing, which minimize the peak pressure of pipes at the valve, can be obtained. By constructing the control program on the valve closing, the water hammer pressure can be reduced effectively, and the active control of water hammer by regulating the valve can be realized.