The invention discloses a plasma thruster based on a multilevel tip cusped magnetic field, relates to the field of plasma thrusting, and aims to solve the problem that the service life is short due to serious sputtering etching of ceramic wall surfaces caused by ions and further solve the problem of low power density of a conventional thruster. The number of circular permanent magnets is larger than or equal to 3; a working medium jet flow hole is formed in the bottom of a circular ceramic cavity body; anodes are arranged on the periphery of the working medium jet flow hole; the inner diameter of the front section A of the circular ceramic cavity body is larger than that of the inner diameter of the rear section C; the side wall of the circular cavity body is sleeved with a plurality of circular permanent magnets sequentially; magnetizing directions of two adjacent circular permanent magnets are opposite; a magnetic conducting ring is fixed between every two adjacent circular permanent magnets; a positive pole of a power supply is electrically connected with the anodes; and a negative pole of the power supply is electrically connected a hollow cathode, and the hollow cathode is located on an outlet side of the circular ceramic cavity body. The plasma thruster is mainly applied to the aerospace field.