Abstract: A Reputation-based Service Differentiated Incentive (RSDI) mechanism is proposed in this paper to solve the selfish behavior of nodes during consciously supporting services efficiently for Mobile Ad-hoc NETworks (MANETs). With a clustering global reputation model and associating services with reputation using grades, RSDI provides differentiated services based on reputation; The nodes which have higher reputation level can consume higher level services, consuming services or refusing to provide services intentionally will reduce nodes reputation, nodes need positively provide trustworthy services to increase their reputation in order to ensure consuming services. Simulations show that RSDI can resist the selfish behavior of nodes, and motivate nodes to positively provide trustworthy services effectively.