An uninterruptible power system and an operation method thereof are provided. The uninterruptible power system has a plurality of function blocks which form a topology structure of the uninterruptible power system. The uninterruptible power system comprises a sensing circuit and a control circuit. The sensing circuit is configured to sense the function blocks and to generate a sensing data accordingly. The control circuit is configured to determine, according to the sensing data, whether an event occurs in any of the function blocks. When the determination is yes, the control circuit generates an event code corresponding to the event and outputs a control command accordingly. The control command is used to control a display interface to display the event code, and is used to control the display interface to send a prompt message through a function block graphic symbol corresponding to the event code in the displayed topology structure.