Abstract: The micro-cathode arc thruster (μCAT) has a broad application prospect in the field of nano-satellites. A kind of co-axial μCAT is developed in this paper. The thruster consists of two concentric electrodes, the titanium one and the brass one, separated by a ceramic insulator tube. Its working principle is as follows: The pulsed high voltage is used to excite an arc, to generate the plasma. The generated plasma is accelerated by the multi-physical field to be ejected from the thruster to generate the thrust force. The parameters of the thruster include the discharge characteristics, the erosive rate of the propellant, the ion current and the impulse bit, and they are measured and analyzed. The experiment shows that this CA-μCAT works well. The ionization rate of the thruster is from 4% to 7%. The thruster’s impulse bit and the specific impulse are 0.485 μN·s and 195.6 s, respectively, without the magnetic field; the values are 1.285 μN·s and 518.2 s, respectively, in a magnetic field of 0.044 T in strength. The average thrust is in the order of 10 μN.