A printing method and a printing system are provided. A printing system comprises a user terminal, a cloud, and at least one authentication server to perform user authentication of at least one image forming apparatus with respect to a user of the user terminal, wherein the cloud receives a registration request for the user with respect to a first image forming apparatus from the user terminal and transmits the registration request for the user including identification (ID) information of the first image forming apparatus and ID information of the user to a first authentication server corresponding to the first image forming apparatus, and receives an authentication request for the user with respect to the first image forming apparatus from the user terminal and transmits the authentication request for the user including the ID information of the first image forming apparatus and the ID information of the user to the first authentication server, and wherein the first authentication server performs authentication in response to the authentication request for the user and transmits a result of the authentication to the first image forming apparatus.