Business access method and device

The service access device includes following units: service adaptation unit (SAU) in use for carrying out communication between its multiple first interfaces in different types and service engines of multiple subsystems of value added service (VAS), thereinto each interface protocol of each first interface is identical to interface protocol of each service engine; provider adaptation unit (PAU) in use for carrying out communication between its second interface and each CP/SP application; logic control unit in use for obtaining information of address interface of specific CP/SP application or subsystem of VAS when PAU receives message or data from specific CP/SP application to be sent to subsystem of VAS in order to for PAU or SAU to send message or data to specific CP/SP application or subsystem of VAS based on the obtained information of address interface. The invention lowers threshold for CP/SP to develop VAS.