A spectrum allocation device, comprising: an allocation unit, configured to allocate a corresponding continuous available spectrum resource to a newly added service of service type i of k possible service types, each possible service type occupying a predefined spectrum width s(i), 1≤i≤k, according to a pre-classified spectrum resource, wherein the pre-classified spectrum resource comprises: a spectrum band M in a first state, a spectrum band M' in a second state, and a spectrum band N in a third state, wherein the spectrum band M in a first state is a spectrum band in an occupied state, and at least one link in the spectrum band in an occupied state is in an occupied state, the spectrum band M' in a second state is a spectrum band in a released state, wherein the spectrum band in a released state is a spectrum band comprising spectrum resources that are released by all services in the spectrum band M in a first state, and the spectrum band N in a third state is a spectrum band N in an unused state, and wherein, if a continuous available spectrum resource having a bandwidth corresponding to the predefined bandwidth of the newly added service of type i exists in the spectrum band M in the first state or in the spectrum band M' in the second state, the allocation unit is configured to allocate a continuous available spectrum resource to the newly added service according to the spectrum band M in the first state or according to the spectrum band M' in a second state in the pre-classified spectrum resource, respectively; and an update unit, configured to update status information of the spectrum resource that is occupied by the newly added service and that is allocated by the allocation unit. an allocation unit, configured to allocate a corresponding continuous available spectrum resource to a newly added service of service type i of k possible service types, each possible service type occupying a predefined spectrum width s(i), 1≤i≤k, according to a pre-classified spectrum resource, wherein the pre-classified spectrum resource comprises: a spectrum band M in a first state, a spectrum band M' in a second state, and a spectrum band N in a third state, wherein the spectrum band M in a first state is a spectrum band in an occupied state, and at least one link in the spectrum band in an occupied state is in an occupied state, the spectrum band M' in a second state is a spectrum band in a released state, wherein the spectrum band in a released state is a spectrum band comprising spectrum resources that are released by all services in the spectrum band M in a first state, and the spectrum band N in a third state is a spectrum band N in an unused state, and wherein, if a continuous available spectrum resource having a bandwidth corresponding to the predefined bandwidth of the newly added service of type i exists in the spectrum band M in the first state or in the spectrum band M' in the second state, the allocation unit is configured to allocate a continuous available spectrum resource to the newly added service according to the spectrum band M in the first state or according to the spectrum band M' in a second state in the pre-classified spectrum resource, respectively; and an update unit, configured to update status information of the spectrum resource that is occupied by the newly added service and that is allocated by the allocation unit.