In optical burst switching(OBS) networks,many proposed multi-path routing mechanisms only consider a service and the researches about multi-path with multi-services are few. However,many proposed multi-path routing mechanisms only consider a service an d the researches about multi-path with multi-service are few.To solve this problem,a new mul ti-path mechanism with service differentiation is proposed in this paper.The mechanism sends probe packets to o btain the load information of multi-service on the multi-path routing without sharing risk link before sending the services with different service levels.According to the load information,the burst loss rate of each service on each route is calculated by Erlang fixed point approximate analysis method.And a rou te with minimal burst loss rate is chosen for the service.In a core node,different services are di fferentiated by the extra offset-based service differentiation method.In this way,by the link state inf ormation,different services are distributed to multi-path routes without sharing risk link,and this helps to reduce the burst loss rate and realize the service differentiation by the multi-path routing.The simulati on results show that the proposed routing mechanism can effectively reduce the burst loss rate and suppor t service differentiation.