The invention provides a magnetron cathode assembly assembly process, including the following steps: S1: pre-assembly between pre-assembled parts and molds; S2: welding, demoulding; S3: leak detection; S4: installation of filaments, upper ends cap, and weld and fix the filament and upper end cap; S5: filament carbonization; S6: resistance detection, titanium powder coating; wherein, the pre-installed parts include lower end cap, long lead wire, reflector, K side tube, solder plate, support Body, terminal assembly; the mold includes an upper mold and a lower mold. The upper mold and the lower mold are set so that the cathode assembly will not be deformed during welding, thereby ensuring the structural accuracy of the cathode assembly, and then through the setting of the upper and lower fixtures of the leak detector, the cathode assembly can be inspected When leaking, it has higher sensitivity and detection accuracy. The cathode assembly assembly process formed by the above mold is used to ensure the assembly accuracy of the magnetron cathode assembly and improve the product qualification rate.