Abstract: In order to study the influences of different electrode structures in low voltage and micro-gap on the discharge micro-characteristics, the particle method (PIC/MCC) is adopted for simulation, and the study of the breakdown discharge under different electrode structures (spherical, cylindrical, and conical) is focused on. In the initial and development processes, through the simulation study of the micron-level electrode spacing, and a comparative analysis with the Paschen curve, it is found that the discharge within the range of 1~4 μm between the electrodes belongs to the field emission mechanism. The influences of the electrode structure on the spatial electric field distribution, particle density, current intensity and discharge channel are analyzed. It is found that the electric field distribution of the tapered electrode and the spherical electrode is locally uneven in the micro gap, and it is easier to form a field emission phenomenon on the surface of the cathode, which impairs the breakdown voltage threshold. At the same time, the influence of the electrode structure on the electric field distribution ultimately affects the field emission intensity of the cathode surface and the effective area formed by the plasma channel, and affects the size of the field emission current and the speed of the discharge channel formation. Experiments have further verified the influences of the electrode structure on the breakdown voltage and discharge time: under the same circumstances, the taper electrode has the smallest breakdown voltage and is the first to break down relative to the spherical electrode and the cylindrical electrode, and the discharge time is the shortest. The breakdown voltage of the cylindrical electrode is the largest and the discharge time is the longest.