Although the time-domain statistic channel model is at present given in the IEEE Ultra-Wideband（UWB）standards

the frequency-domain characteristics of channels are not reflected distinctly.However

they have critical impacts on UWB channel capacity

ranging precision

etc.Therefore

the frequency-dependent path loss of UWB Non-Line-of-Sight（NLOS）environment is modeled and frequency-dependent path loss indexes is fitted on the basis of the measured data

the variation law of frequency-domain attenuation in the NLOS transmission environment is obtained.The study results indicate that the high-frequency statistical attenuation characteristics are especially evident in the indoor NLOS environment

which is obviously different from the normal analytical results.The analysis method and conclusions in this paper have fairly strong instructive significance to the evaluation of UWB communication capacity and ranging precision in different NLOS environments.