The statistical 73 breakdowns for 5 CINRAD/CC radars at Yunnan in the recent 5 years have discovered that the failure from launching system magnetic field power reaches 21 times, relatively speaking, the failure rate of magnetic field power source is high. Through analyzing and inducing the elimination processes of 21 magnetic field power failures, we summarize, examines and analyzes the computing technique for the magnetic field power failure, have given the essential test point profile, the debugging target, as well as causes for radar parameters and emission power, klystron change situations and the debug method, which can be references for the technical support personnel. Meanwhile, take a Wenshan CINRAD/CC typical fault analysis and the eliminaton as an example, has presented the above method and the target specifically, and use the practical experience obtained through the elimination process of failure many times, then replace the primary device often possibly to bring some radar performance parameters to change, easy to cause other breakdowns, therefore after proposing the trouble shooting, the paddingsystem related is very important.