The invention relates to an assembly type hollow cathode heater comprising a cathode pipe, a front positioning ring, a ceramic framework, a heater strip, a ceramic jacket, a rear positioning ring, a lead wire pipe and an emitting body, wherein the ceramic framework is sleeved at the excircle of the cathode pipe in a tightly matching way; the emitting body is sleeved in the cathode pipe; the ceramic jacket is sleeved on the ceramic framework wound with the heater strip; the front positioning ring and the rear positioning ring are welded on both ends of the ceramic framework and the ceramic jacket; one end of the heater strip is welded on the cathode pipe, and the other end of the heater strip is sleeved on the lead wire pipe. When the assembly type hollow cathode heater starts, voltage of 10-15V is applied between the lead wire pipe and the cathode pipe so that the heater strip generates current of 8-12 A and lasts for 3 minutes-5 minutes to heat the emitting body to 1500 K-1800 K, thus the emitting body has electronic emission ability. The assembly type hollow cathode heater has simple structure, easy manufacture and high finished product ratio and reliability and can be used for a xenon ion thruster, a Hoare thruster and a plasma source hollow cathode assembly.