In the current routing mechanism for Mobile Ad hoc Networks, service differentiation is not realized completely, resulting in resources wastage for best-effort (BE) traffic and deficiency for real-time traffic, such as voice and video. A novel service differentiated multi-path routing mechanism is proposed, in which service differentiation is realized in network layer based on multi-path routing. Multiple paths found in the route discovery procedure are evaluated, sorted and chosen according to the packet service type. Simulations show that the resource requirement of real-time traffic is better satisfied and the overall performance is improved effectively, that is, the end-to-end delay is decreased and the packet delivery ratio is increased evidently.