This paper is to design an intelligent weighing system to solve the problems in enterprises, such as incompatibility with hardware and software environment in different enterprise scenarios, the fixed interface layout and the dilemma that a single-way computational formulas can not fit the workflow of complementation of weighing system flexibly . A self-defining formula method is proposed to meet different demands from variable enterprises, which is solved by infix expression algorithm. The interface layout is screen self-adaptation by using an alterable resolution algorithm. The result of the experimental study reveals that the intelligent weighing system is more flexible in self-adaptation of environment than the traditional weighing system.