Liquefaction of sand soil such as silty sand was quite popular in earthquake. Gravel liquefaction, by contrast, was seldom. Soil liquefaction was popular in Chengdu Plain in Wenchuan Earthquake and there was ejeched gravel in several sites. Through drilling and tests for typical liquefied sites, the study on distribution of layers, compactedness , shear wave velocity, particle size distribution had been performed. The results shows: (a) Soil distribution is similar in 2 typical liquefied sites which are located in different location and different seismic intensity regions. Gravelly sand was the only cohesiveless soil which is possible to be liquefied,so gravel liquefaction was true; (b)The liquefied gravel was the characteristics of shallow, loose , low shear wave velosity and. the Holocene sediment. (c) Particle graduation of liquefied gravelly sand was poor and there was a short of soil fraction.