Information of the earth’s free oscillation can be used to infer the layered structure of the earth and focal mechanism of the earthquake which excited the osillation. In this study

according to VHE and VHN data recorded in 3 days by 7 stations of China Digital Seismograph Network （CDSN） for Nov. 14

2001 earthquake to the west of the Kunlun mountain pass

we extracted toroidal mode of 0T2

0

T40 of the earth free oscillation using power spectral density （PSD） estimation. Because the frequency band of seismograph in China digital seismograph network suppress information of solid tide

it is not necessary to remove the solid tide in our process. Our result is nearly consistent with frequency of the modes of preliminary reference earth model （PREM）. The inconsistent modes of toroidal free oscillation may be resulted from lateral heterogeneous or/and anisotropic media of

the earth. Thus the data of the earth toroidal free oscillation can be used to explore the 3-dimensional structure （density structure

velocity structure） or anisotropy of the earth and help to disclose the convection mode in the whole mantle or in the upper mantle.