Abstract: In this paper, it aimed at the cavity structure and characteristic of certain type klystron making certain interrelated analysis which is emphasized on the drift tube and magnetic field﹑the tune organ and the loading method. The result indicated that it could be formed a similarly TWT magnetic field by the iron drift tube, simultaneously it made some analysis about the type of magnetic field combining the Characteristic of tube. It also found out that the structure of the tune organ is simple, the loading method could be provided a new idea. In a word it could be offered some references for our further research on the correlation design of the structure and electricity capability.