The open-type wharf is widely used in port engineering.Due to the complexity of load combinations,calculation that covers full load combinations usually costs a lot of time.When simplification is applied,accuracy will be sacrificed or most dangerous load combination may be missed.An automatic calculation method is put forward and corresponding data management platform is built on SQLite and Python. Load effect is calculated on single effect by Staad.First of all,the distribution polymorphism of generalized uniform and generalized mobile loads is dealt with,then the load effect of discrete position of all members is computed.Envelope diagram is the final output of this method.The method greatly reduces computational complexity and highly increases efficiency.The achievement of this article makes refined and accurate design possible.