Large-scale shaking table tests are conducted to evaluate seismic earth pressures acting on an embedding footing during soil liquefaction. The threshold soil displacement relative to the footing, above which the earth pressure begins to increase, increases with the development of loosened zones around the footing. A new seismic earth pressure theory considering the loosened zones is developed, by extending the one proposed by Zhang et al. (1998). The earth pressures evaluated by the proposed method show good agreement with those observed in the tests.