For an explosive source used in seismic exploration, evaluating its seismic wave energy caused by explosives exploding in the soil is an important issue. The direct method, calculating RMS amplitude of the seismic wave propagation in different time fields, is usually used to appraise this seismic wave energy. However,the result of calculating is not only comparatively imprecise, but also the analysis on the records of seismic wave is very complex and much labor-consuming. Even so an easier and more economical way for evaluating the energy of blast-induced seismic wave is needed. In this paper, a potential pressure measuring method in the elastic zone is proposed. The experimental results showed that under the same geological condition and the same experiment condition, the characteristic of pressure wave in the elastic zone is applicable to evaluate the energy of blast-induced seismic wave.