The next generation(4G)wireless network is envisioned as a convergence of different wireless access technologies.A vertical handoff is a handoff between access networks with different wireless technologies.We present a speed sensitive vertical handoff algorithm.No need of the accurate position and speed information of the mobile host

it takes into account the influence of velocity based on the history results of received signal strength measurements.This algorithm can automatically adapt to the mobile host’s velocity and improve handoff efficiency.Simulation results show that the proposed algorithm can achieve better performance compared with conventional handoff decision algorithms.