Pressure-resistant high-power emulsified seismic source powder column and its preparation method, the ratio of raw materials is: ammonium nitrate 74-92, sodium nitrate 0-11, crystal modifier 0-16, water 3-10, composite wax 4 ~6, emulsifier 1~2, microsphere foaming agent 0.1~1, aluminum powder 3~6. The method includes: A, water phase solution preparation; B, oil phase solution preparation; C, continuous emulsification; D, high temperature sensitization and addition of aluminum powder; E, automatic drug charging; F, sealing, cold medicine, packaging. The invention has the advantages that: the pressure-resistant high-power seismic source charge column has good pressure-resistant performance, can detonate normally when the pressure in deep water is 0.3 MPa, and has high explosive power. At the same time, since the density regulator used is a microsphere foaming agent, it can be sensitized under the condition of 100-120°C. The sensitized material has a high temperature and good fluidity, which is beneficial to the automatic powder filling machine. Improve work efficiency.