A method for providing a user-customized service, executed by a system comprising a server (320; 420; 520; 620), a device (330, 340; 430, 440; 530, 540; 630, 640) and a terminal (310; 410; 510; 610), the method comprising: storing, in the server, user information including first identification information of a terminal (310; 410; 510; 610), and, through registering by the device, device information (335, 345, 435, 445; 535, 545; 635, 645) including second identification information of a device (330, 340; 430, 440; 530, 540; 630, 640), a category of the device, and executable functions of the device according to the category; transmitting, by the terminal, a request message including the first identification information; detecting, by the device, the first identification information of the terminal (310; 410; 510; 610) transmitted by the terminal with the request message; transmitting, by the device, to the server, a message including the second identification information of the device and the detected first identification information; receiving, by the server from the device, the message including the second identification information and the first identification information detected by the device; determining, by the server, operation information for performing a specific function of the executable functions of the device based on the stored user information corresponding to the received first identification information and the stored device information corresponding to the received second identification information, the category of the device, and the executable functions of the device according to the category; and transmitting, by the server to the device, a command message including the operation information for performing a specific function of the executable functions; receiving, by the device, from the server, the command message including the task for performing the specific function of the executable functions corresponding to the terminal, and performing, by the device, the specific function of the executable functions according to the command message. storing, in the server, user information including first identification information of a terminal (310; 410; 510; 610), and, through registering by the device, device information (335, 345, 435, 445; 535, 545; 635, 645) including second identification information of a device (330, 340; 430, 440; 530, 540; 630, 640), a category of the device, and executable functions of the device according to the category; transmitting, by the terminal, a request message including the first identification information; detecting, by the device, the first identification information of the terminal (310; 410; 510; 610) transmitted by the terminal with the request message; transmitting, by the device, to the server, a message including the second identification information of the device and the detected first identification information; receiving, by the server from the device, the message including the second identification information and the first identification information detected by the device; determining, by the server, operation information for performing a specific function of the executable functions of the device based on the stored user information corresponding to the received first identification information and the stored device information corresponding to the received second identification information, the category of the device, and the executable functions of the device according to the category; and transmitting, by the server to the device, a command message including the operation information for performing a specific function of the executable functions; receiving, by the device, from the server, the command message including the task for performing the specific function of the executable functions corresponding to the terminal, and performing, by the device, the specific function of the executable functions according to the command message.