When facing with multiple Web services with the same or similar functionality, QoS (quality of service) has become an important criterion for users to select the appropriate Web services. We present a QoS model, the QoS attributes are divided into exact numeric type, interval numeric and Triangular fuzzy numeric. We propose a kind of multi-attribute group decision-making model based on TOPSIS (echnique for order preference by similarity to an ideal solution) to select Web services, which considers weights of multiple decision makers and weights of the QoS preference in the decision process. The example proves that the method is feasible.