Regarding at the calculation of mooring force of windproof single point mooring system in harbour engineering，the equilibrium position of the ship under wind，wave and current loads is obtained according to Load Code for Harbour Engineering and Daidola formula.On this basis，the instantaneous wave impact force is superimposed，and the force model of the mooring system is established.Considering that the mooring ship will produce sway motion under the combined action of wind，wave and current，referring to the relevant formula form in the military standard Anti-typhoon mooring buoy system，and comparing the results of physical model test，the combined correction coefficient of wind，wave and current forces is proposed，which provides a solution for engineering application.The method in this paper can be used for the engineering under similar conditions to preliminarily determine the parameters of windproof buoy，and provide a necessary basis for subsequent physical model tests.