The　quality　of　service　guaranteed　multicast　routing　problem　(QoS-MRP)　is　an　important　issue　in　wireless　mesh　networks　(WMNs).　However,　the　multicast　routing　is　NP-complete　problem.　In　this　paper,　this　problem　is　transformed　into　a　multi-objective　combinatorial　optimization　problem.　We　present　an　improved　discrete　particle　swarm　optimization　(PSO)　approach　for　QoSMRP　which　takes　many　key　QoS　parameters　into　consideration　and　gives　a　good　compromise　between　them.　The　proposed　algorithm　was　compared　with　SPT,　KPP　and　an　enumeration　method.　The　simulation　results　show　that　this　algorithm　is　effective　and　fmds　high　quality　solutions　for　QoS-MRP.　©　2010　IEEE.