For the application requirement of a carbon nanotube clod cathode (CNCC) used in the microwave and millimeter wave electric vacuum radiation source devices, pulsed field emission characteristics of CNCC are experimentally investigated by a 2 μs/20 kV high-voltage modulator in this paper. The pulsed field emission currents for different distances between anode and cathode and those of CNCC after the pulsed high-tension arc has occurred many times are studied. A maximal emission current of 16 mA is tested for CNCC with a 4 mm diameter emission disk, and the emission current density is achieved to be 127 mA/cm2. Based on the experimental results, the field emission simulation model of CNCC is established by PIC simulation software. Simulation results show that this simulation model is suited for describing the experimental results and laying the foundation for the development of CNCC electron optical system and radiation source devices.