Abstract: The essential design procedure about discharge chamber are presented in this paper,it includes magnetic field,geometric texture,the number of magnetic poles,neutral atoms distribution method and the key parameters.It is divided into length diameter ratio,poles position,magnet size,cathode position.Design and development of discharge chamber of LIPS-300 ion thruster was completed following the procedure noted above.At last,the performance of the discharge chamber is analyzed and tested by simulated analysis and actual experimental data.The ultimate result is the discharge loss and beam flatness of four ring-cusp magnetic fields is better than those of three rings.