Analyse the partition of bandwidth between uplink and downlink in CDMA cellar system on the basis of the inputting C/I of a receiver and the channel model presented by T. S. Rappaport and L. B. Milstein, and gives the method of the asymmetrical partition of bandwidth. The simulation results are also presented，showing that the frequency asymmetrical partition between uplink and downlink enhances the capacity of CDMA cellar system.