A method of changing the setting of mobile unit by broadcasting message is provided. Firstly, the broadcaster codes the setting information into an application program via message editing such. Then, the message is broadcasted to associated mobile units according to the numbering of the mobile unit. When the starting time is up, the original setting of the mobile unit will be shifted to a situational setting according to the setting information; whereas when the finishing time is up, the situational setting will be shifted back to the original setting and all previous settings will be restored. Lastly, the system terminal receives and writes the mobile phone information into a registry, then broadcasts the setting information to the mobile phone within the specific area, enabling the mobile phone to change relevant settings accordingly. Mobile phones outside the specific area cannot receive the broadcasting signal and will not be affected.