A check-in method for a reserved room provided with a smart lock, the method comprising: obtaining, by a mobile terminal, a device identifier of a smart lock by communicating with the smart lock through wireless communication, and sending a user identifier and the device identifier to a service server; searching, by the service server, for identity information of a reservation user corresponding to the user identifier from a reservation database, wherein the reservation database is stored in the service server and stores the user identifier, the identity information of the reservation user, and its corresponding room reservation information; sending, by the service server, the identity information of the reservation user and the device identifier to a processing server; identifying, by the processing server, matching biometric feature information from a biometric feature database in the processing server using the identity information, the biometric feature database storing biometric feature information for each user having made a room reservation; generating, by the mobile terminal, request information for a digital key for unlocking the smart lock, and sending the request information to the processing server; receiving, by the mobile terminal from the processing server, a collection request for collecting biometric feature information that is generated based on the request information; collecting, by the mobile terminal, corresponding biometric feature information based on the collection request, and sending the corresponding biometric feature information to the processing server; performing, by the processing server, user identification by using the corresponding biometric feature information and the matching biometric feature information; when the user identification is successful, identifying, by the processing server, based on the device identifier, a smart lock information corresponding to the device identifier from a smart lock database stored in the processing server; generating, by the processing server, the digital key for unlocking the smart lock based on the request information and the smart lock information, and sending the generated digital key to the mobile terminal; receiving and storing, by the mobile terminal, the digital key for unlocking the smart lock; and unlocking, by the mobile terminal, the smart lock by using the digital key. obtaining, by a mobile terminal, a device identifier of a smart lock by communicating with the smart lock through wireless communication, and sending a user identifier and the device identifier to a service server; searching, by the service server, for identity information of a reservation user corresponding to the user identifier from a reservation database, wherein the reservation database is stored in the service server and stores the user identifier, the identity information of the reservation user, and its corresponding room reservation information; sending, by the service server, the identity information of the reservation user and the device identifier to a processing server; identifying, by the processing server, matching biometric feature information from a biometric feature database in the processing server using the identity information, the biometric feature database storing biometric feature information for each user having made a room reservation; generating, by the mobile terminal, request information for a digital key for unlocking the smart lock, and sending the request information to the processing server; receiving, by the mobile terminal from the processing server, a collection request for collecting biometric feature information that is generated based on the request information; collecting, by the mobile terminal, corresponding biometric feature information based on the collection request, and sending the corresponding biometric feature information to the processing server; performing, by the processing server, user identification by using the corresponding biometric feature information and the matching biometric feature information; when the user identification is successful, identifying, by the processing server, based on the device identifier, a smart lock information corresponding to the device identifier from a smart lock database stored in the processing server; generating, by the processing server, the digital key for unlocking the smart lock based on the request information and the smart lock information, and sending the generated digital key to the mobile terminal; receiving and storing, by the mobile terminal, the digital key for unlocking the smart lock; and unlocking, by the mobile terminal, the smart lock by using the digital key.