In recent years, web services open the way to global business development through B2B integration and they used with different business applications to accommodate their services. So while selecting a service, the first preference is given to the functional properties of the web service and then a best web service is selected from the list by considering the expected quality. The QoS of a web service is also depends on the variant nonfunctional parameters of its service which may subject to changes because of network and other related factors. While considering the performance of a service, the overall quality is always preferred but the actual functionality of the service is based on the weight fixed for the non functional parameters like response time, throughput, etc... So assigning functionality based weight for the non functional parameters are used to achieve the assured quality of the service. In this paper we are proposing the system that gives importance for the non functional parameters such as response time, throughput, availability, success ability, reliability for which the weight is set based on functionality and requirement of aparticular business application.