Service discovery is an essential element in pervasive computing environment. The involvement of only the needed users and service providers for a service discovery in pervasive computing environment is challenging. To protect their privacy, neither side is willing to expose their information first. A incrementally progressive exposure approach is used to solve the problem in this paper. In the approach users and service providers expose partial information in turn and avoid unnecessary exposure if any mismatch occurs. To reduce the unnecessary match after an exchange especially the first round, a segment is randomly picked from the information and exchanged with the partial information together. To reduce the number of exchange, we gradually increase the length of exchange message if a match occurs.