In this paper

a new leaky bucket （LB） scheme based on dynamic buffer thresholds is presented

of which the buffer thresholds change with the leaky rate.By an embedded Markov process

we obtain the limiting distribution of the system’s state at an embedded point and at an arbitrary time when using Markov modulated Poisson procedss（MMPP） as an input traffic.So cell loss probability and mean cell delay and effective bandwidth occupancy are easily obtained.Numerical result shows our scheme has lower cell loss probability and lower mean cell delay than those of other LB schemes

and significantly needs less bandwidth resource.