The present invention relates to a method for controlling a system comprising a mobile terminal for a guardian and a mobile terminal for a child. A method for controlling a mobile system comprising a first terminal and a second terminal, according to an embodiment of the present invention, comprises the steps of: transmitting a request message from the first terminal to the second terminal using a user input applied to the first terminal; determining, by the second terminal, whether the transmitted request message satisfies a preset first condition or not; processing, by the second terminal, a control command, which corresponds to the transmitted request message, on the basis of the result of determination regarding the first condition; transmitting a response message, which reflects the result of processing, from the second terminal to the first terminal; determining, by the first terminal, whether the transmitted response message satisfies a preset second condition or not; and processing, by the first terminal, a control command, which corresponds to the transmitted response message, on the basis of the result of determination regarding the second condition, wherein the request message and the response message use a short message service (SMS), and content of the request message and that of the response message are formed on the basis of a preset protocol.