This paper gives an outline of historied observations of gravita-tional earth tide in Lanzhou, and the tidal gravity parameters measured by different instruments. Comparative analyses about observation data, monthly harmonic analysis, and repeated accuracy of major-wave tidal factor between GEO-765 and modified GS11-150 gravimeter are made. The seismic monitoring capacity by using modified GS11-150 gravimeter in Lanzhou is evaluated. Finally, the part of results measured by old GS11-150 in Tianshui, Gansu Province is also introduced.