Based on existing routing Algorithm

we propose a fast algorithm called FGMRA (Fast Group Multicast Routing algorithm) for group multicast by using two strategies.One is to make the best of calculation in existence.Another is to enlarge the storage spaces to get high speed.Compared with algorithm proposed by C.P.Low and N.Wang

the total cost of multicast trees created by two algorithms is almost equal

but our algorithm is faster.The simulation result shows that FGMRA is fast

stable and efficient

and can be used widely.