The present invention discloses a system for controlling the display size of a formula bar in a spreadsheet. The system for controlling the display size of the formula bar and a formula bar module are parallel in a main window module of a spreadsheet application, and the system includes a sub-system I which controls the display state of the formula bar and a sub-system II which controls the display range of the specific content in the formula bar. The system continuously executes real-time detecting and measuring of the aforementioned formula bar module while the application is running, and acquires data on the size of the formula bar from the aforementioned formula bar module. If the acquired data exceed the prescribed range, then it issues a command to the aforementioned formula bar module requesting a change in the size of the formula bar. In the mean time, it issues a command to the aforementioned sub-system I and the aforementioned sub-system II.