Comparing with the traditional mooring line,the automated mooring system is faster in mooring and departure operation and safer and more reliable.At present,there are many engineering examples of automatic mooring system in foreign countries,but the main specifications of port engineering in the world have not been incorporated into the specific design methods of automatic mooring system.Currently,the calculation of the automatic mooring system generally needs to be carried out through more complex numerical simulation,which is not conducive to the design of the early stage of the project.In view of this situation,the paper analyzes the mechanical characteristics of the automatic mooring system,and assumes the mechanical model according to its mechanical characteristics.Combined with the current international and domestic codes about the calculation method of ship external force,the simplified calculation method of the automatic mooring system is derived.This method can be used for designers to calculate the forces on the automatic mooring system in the early stage of the project.