A service switching system, comprising at least two service processing subracks, at least one optical cross-connect subrack, and a bandwidth control unit, wherein each service processing subrack is connected to each optical cross-connect subrack by using an optical fiber; each service processing subrack is configured to: perform service switching for an externally inputted service data electrical signal, convert the service-switched service data electrical signal into an optical signal, and send the optical signal to one or more optical cross-connect subracks; and/or receive a service data optical signal that comes from one or more optical cross-connect subracks, convert the optical signal into an electrical signal, perform service switching, and output the service-switched service data electrical signal; and each optical cross-connect subrack is configured to: receive a service data optical signal that comes from one or more service processing subracks, perform optical cross-connection for the received optical signal, and output the cross-connected optical signal to the one or more service processing subracks; wherein each service processing subrack is connected to the bandwidth control unit; and the bandwidth control unit is configured to perform bandwidth control for the service processing subracks when the service processing subracks perform service switching for different services; characterized in that the service processing subrack comprises at least one service processing unit, at least one electrical switching unit, and at least one interface adaptation unit, wherein the service processing unit is configured to: perform service processing for an externally inputted service data electrical signal, and send the service-processed service data electrical signal to the electrical switching unit; and/or receive and process a service-switched service data electrical signal sent by the electrical switching unit, and output the processed service data electrical signal; the electrical switching unit is configured to: receive the service data electrical signal sent by the service processing unit, perform service switching according to switching control information sent by the bandwidth control unit, and send the service-switched service data electrical signal to the interface adaptation unit; and/or receive a service data electrical signal from the interface adaptation unit, perform service switching according to switching control information sent by the bandwidth control unit, and send the service-switched service data electrical signal to the service processing unit; and the interface adaptation unit is configured to: receive the service data electrical signal sent by the electrical switching unit, convert service data from the electrical signal into an optical signal according to adaptation control information sent by the bandwidth control unit, and send the optical signal to the optical cross-connect subrack; and/or receive a service data optical signal sent by an optical cross-connect subrack, convert service data from the optical signal into an electrical signal according to adaptation control information sent by the bandwidth control unit, and send the electrical signal to the electrical switching unit.