The conventional Software Configuration Management (SCM) tools have shown their weakness in large and complex software systems with the development of modern software. This paper provides a better SCM tool with high availability to facilitate software development process. A novel approach named Quality of Service (QoS)-based SCM (QSCM) is presented, which introduces QoS guarantee techniques at the application level to web-based SCM system in order to improve SCM system?s performance. QSCM classifies users together with SCM activities and treats with requests according to their priority. When the server is overloaded, it stops treatment with new requests so that to avoid from crash. The work described here is a first step towards this goal.