The emulsion base pressed by dynamic pressure was studied,and the micro-photography was used to explore the microstructure changes of emulsion base. The results show that the destruction of the sensitizing carriers and the microstructure changes of the emulsion explosives are the reasons of the desensitization,and the destruction of the sensitizing carriers is the main reason. The explosion behaviors of three kinds of emulsion explosives pressed by dynamic pressure were studied. The results show that the anti-pressing property of emulsion explosive sensitized by glass micro-balloon is the best,sensitized by chemical bubbles is the better and sensitized by expanded perlite is the worst. The critical desensitization pressures of the three kinds of emulsion explosives are 134.66 MPa,99.83 MPa and 27.13 MPa,respectively.