The selection of an appropriate web service for a particular task has become a difficult challenge due to the increasing number of web services offering similar functionalities. Quality of web services (QoS) becomes crucial for selecting web services among functionally similar components. However, it remains difficult to select an interesting Web services from a large number of candidates with a good compromise between multiples QoS aspect. In this paper, we propose a novel concept based on dominance degree to rank functionally similar services. We rank Web services by using a fuzzification of Pareto dominance called Average-Fuzzy-Dominated-Score(AFDetS()). We demonstrate the effectiveness of the AFDetS through a set of simulations by using a real Dataset.