Abstract: Based on the collection and statistical analysis of the radiation monitoring instrument calibration data, and taking the typical GIM204 gamma dose rate monitoring device as an example, the feasibility is demonstrated by the experience feedback method, to adapt to the implementation of the refueling scheme for a long period of time in Tianwan nuclear power station. Studies have shown that when the calibration cycle of GIM204 is extended from1 year to 1.5 year, the relative calibration error does not exceed the allowable values, and satisfies the requirement on refueling cycle extension.