介绍了利用平底孔相对于大平底面声压反射率的分贝差值来测试超声波探头在实际探伤中的工作频率，消除因探头频率误差给缺陷定量、定性带来的不利因素，提高探伤结果的准确性． This paper introduces the use of the difference of the decibels of the sound pressure reflectivity of the flat bottom hole to the large flat surface to test the working frequency of the ultrasonic probe in the actual flaw detection and eliminate the unfavorable factors caused by the qualitative and quantitative error of the probe frequency to improve the accuracy of the flaw detection result Sex.