Abstract: In this paper a new buffer management scheme called DT+SMA is presented. This scheme combines sharing with minimum allocation (SMA) and dynamic threshold (DT) arithmetic, and we find it has the benefits of both DT and SMA. Through analysis the scheme in theory and simulation we can see that actually DT+SMA is better than SMA in fairness in single priority, and is easier to apply in multiple priorities model than DT when achieving the similar performance with DT.