Abstract: A numerical method and computer program for non-symmetrical contraction flow of a water tunnel are described in this paper, which use the finite volume approach to solve the unsteady Euler equation, the basic algorithm is the explicit predictor-corrector scheme of MacCormack. For several typical contraction curve, the three-dimensional flow field calculation is made, the wall pressures along the centerlines or corner lines at top or bottom and velocity distributions of exit section are obtained, the results are compared to choose the optimal contraction curve to meet the design needs. It is shown that this approach and program are valid for the three-dimensional contraction design.