Apparatus and method for WS-Policy based web service controlling. The apparatus includes: a service policy repository for storing a plurality of Web Service policies; a service policy agent for receiving a request for a Web Service policy from a service consumer and for obtaining conditioning information that influences the Web Service policy; and a service policy conditioner for selecting corresponding Web Service policy from the service policy repository in accordance with the conditioning information. The service policy agent sends the Web Service policy to the service consumer. The Web Service policy-based service differentiation method decouples the service differentiation mechanism from the service provision and service invocation mechanism and can provide policy support in accordance with other nonfunctional conditions besides service functions.