The utility model relates to a choke coil of a magnetron, which comprises a three-segment choke coil, wherein the three-segment choke coil comprises a sparse wound coil (1), a first close wound coil (2) and a second wound coil (3) that are connected in series. The utility model is characterized in that one end of the sparse wound coil (1) is connected with a cathode terminal side of the magnetron,the other end is connected with one end of the first close wound coil (2), the other end of the first close wound coil (2) is connected with one end of the second wound coil (3), the other end of thesecond wound coil (3) is connected with a terminal of a core capacitor, and a ferrite magnetic core (4) is arranged inside two segments of the wound coils. With the three-segment choke coil, the utility model has advantages of good wave filtering performance, effective reduction of the noise produced from the input side of the magnetron, and improved electromagnetic compatibility of the continuous wave magnetron. The magnetron of the utility model is reasonable in design and is excellent at performance.