The natural frequency characteristics of field has the remarkable influence to the field acceleration response. This paper realized the free field liquefaction numerical simulation experiment based on the Finn model, simultaneously performed the elastic field acceleration response comparative experiment, and has studied the acceleration response frequency features question of liquefiable field. The results indicated that, the acceleration response essential feature of liquefaction field is low-frequency amplification, high frequency reduction. The low-frequency amplification effect is higher than the high frequency reduction effect obviously. The acceleration is amplified in early time and is weakened in later period during the liquefaction process. The acceleration amplification in liquefiable field is remarkable for inputting low frequency waves, the acceleration response is 13 times to input value. Elastic fields also have “low-frequency amplification, high-frequency deflation features”, However, this feature of elastic field is not significant as liquefiable field. At the lower position of liquefiable field acceleration amplification is the largest, at the surface of elastic field acceleration amplification is maximum. The underground structure seismic design in liquefiable field was carried on as in the conventional elastic field, then caused the underground structure to be at the dangerous condition. Researching results will provide a theoretical and experimental basis for the dynamic analysis of underground structures passing through liquefaction soil layer.