Although loess liquefaction is not very common during earthquakes in Northwest of China, it is disastrous if it happens. Both study and valid evidence from Haiyuan 8.5 Earthquake in 1920 and Tajikistan 5.9 Earthquake in 1989 have proved that loess liquefaction could be very disastrous under certain conditions. In this paper, the criterions of loess liquefaction are discussed to show that unlike typical liquefaction of sand, loess which falls into the category of both silt clay and clayey silt has unique characteristics during liquefaction test. To predict liquefaction of loess, a simple method based on laboratory test and field evidences using GIS is proposed. The prediction results and corresponding measure have been adopted in Seismic Design Code for Buildings in Lanzhou Urban Area. Finally, recent approach of treatment of loess with chemicals methods is developed, which may have some application implication as an simple and feasible treatment method against liquefaction of loess
