It is shown by both model tests and theoretical analyses that the dynamic response of taut moored platforms subjected to regular waves can be divided by two kinds of curves into three categories, harmonic response, non-linear response with snap loads and other non-linear response. A new theory to analyze the snap load is proposed. This theory consists of time combinations of solutions of the linear differential equations corresponding to several kinds of wire states. The characteristics of the non-linear response with snap loads are clarified qualitatively and also quantitatively by the theoretical calculations and the model tests.