Abstract: Carbon nanotube is an ideal cold cathode material because of its good field emission characteristics. In order to develop field-emission carbon nanotube cold cathode devices, the characteristics of three kinds of mesh grid structures on carbon nanotube cold cathodes are simulated by using three-dimensional PIC simulation software. The properties of hexagon mesh, triangle mesh, and square mesh are investigated by calculating the electric-field distribution on the surface of cold cathode and field emission beam current pass rate. Simulation results show that the hexagon mesh characteristics is the best. The optimal mesh size of hexagon mesh is obtained and the maximum current pass rate is 75%.