Abstract: In this paper, we present a new structure cathode named co-axis double annulus cathode. By modeling and solving the Laplace equation, we get the accurate distribution of potential in the diode, through which we have the connection of parameters to get the double annulus cathode emissions simultaneously. The CHIPIC particle-in-cell software was used to a simulate the electrons explosive emission of the double annulus cathode with appropriate parameters. The result verifies that, the emitting current density of the double annulus cathode is determined by both the original E-field distribution in the diode and the screening effect between two cathodes. The screening effect factor of one cathode has a linear relationship with the beam emitted from the other cathode and an exponential relationship with the distance between the two cathodes.