Abstract: This paper presents the structural design of two types of nonintercepting gridded gun (i.e. unigrid and tetrode nonintereepting gridded gun). The basic method of the cathodegrid structural design and calculating method of the cathode geometrie usage factor are given. Hence the optimum grid mesh numbers, the dimensions of the grid cells and grid web width are reasonably determined. Also this paper presents the me-thods of machining and aligning the grid for the cathode-grid assembly. The phenomena of breakdown in the electron gun is discussed.