Abstract: The fourth generation mobile communication network is a network that will merge various networks and cover the same area through all of them.In the overlapping coverage area,several networks provide services for a certain subscriber and the handover is necessary.On the other hand,each network has different characteristics,in order to improve each network characteristics,we proposed a new algorithm to establish one data tune between CDMA2000 and Wireless LAN.The simulation test shows that the new algorithm can get higher data rates and efficiently utilize both of the two networks frequency.