The potential interference of ultra wideband (UWB) on existing narrowband wireless communication systems must be analyzed before it is applied, so the paper uses a method based on the physical layer model to analyze the compatibility of direct-sequence ultra wideband (DS-UWB) and multi-band ultra wideband (MB-UWB) on several narrowband victim systems. Based on the physical layer models of PAM-DS-UWB and PPM-DS-UWB and MB-UWB and these victim systems, depended on the communication condition of victim systems, the power restrictions of UWB are obtained on the operating frequency band of N-CDMA, GSM, WLAN systems. The results can offer a solution for the compatibility between UWB and these victim systems.