Ion thruster

The invention discloses an ion thruster. A main cathode is provided with a main cathode channel, an ionization chamber is provided with an inlet channel, and propelling gas is injected into the ionization chamber through the main cathode channel and the inlet channel; the main cathode is used for emitting electrons to the ionization chamber to collide with the propelling gas to be ionized into positive ions and electrons, and gas in the ionization chamber is in a plasma state; accelerating grids comprise electron accelerating grids and the ion accelerating grid, the ion accelerating grid is located in the center, and the electron accelerating grids are located on the two sides; positive voltage is applied to the electron accelerating grids, and the electrons are accelerated from the ionization chamber and emitted out from a screen grid and electron accelerating grid holes; and negative voltage is applied to the ion accelerating grid, and the positive ions are accelerated from the ionization chamber and emitte