Based on 155 horizontal-component digital seismograms of 23 earthquakes recorded by 7 stationsof Urumqi Digital Tele-seismic Network and the Kuerle regional station

which have been formally runsince 2001

the inelastic attenuation

geometric spreading pattern of the central and eastern Tianshan re-gion

as well as the site response of each station were investigated. Firstly

the signals were corrected forinstrumental responses. Then

we adopted a lag-window spectral technique to obtain a stable Fourier spec-trum of the signals and noises. By subtracting the noise spectrum from the signal spectrum

the noise-cor-rected Fourier amplitude of displacement was obtained. Assuming a hinged tri-linear geometrical spreadingmodel directly following Atkinson

we corrected the spectra

and furthermore used the joint-inversion todetermine the inelastic attenuation co-efficiency C（f） and Q（f） by performing regression iteratively. Final

-ly

the tri-linear geometrical spreading pattern were obtained. When hypocenter distance

R

is less than68 km

which corresponds to attenuation of the direct-wave

the wave attenuated with R

-1

. When R is be-tween 68 and 113 km

which corresponds to a transition zone as the direct-wave is joined by post-criticalreflections from mid-crustal interfaces and Moho discontinuity

the energy of S almost does not attenuate.When R is greater than 113 km

which corresponds to attenuation of multiply reflected and refracted Swaves

the wave attenuated with R

-0.5

. The frequency-dependent Q in this region is estimated as Q（f）=344·f

0.55

which is consistent with the seismic activity in this area

characterized by frequently small tomoderate earthquakes but lack of large earthquakes. This study pays the way for the future seismologicalresearches in this area

including recovering the real source spectrum

modeling the ground motion

etc.