Abstract: With the extensive application of the eddy current testing in the inspection of thin-walled tube in China, the evaluation of the uncertainty of the test results is becoming more and more important. There are many factors that affect the uncertainty of test results in the eddy current thin-walled tube inspection technology. For example, the performance of eddy current inspection instrument and eddy current probes, the selection of detection technology, the accuracy of calibration tube, and the choice of filling coefficient, etc., will have an impact on the detection results. In addition, the defect property, burial depth and defect development trend of inspection products will also have an impact on the detection results. This paper analyzes the uncertainty of amplitude, phase and depth of defects measured by eddy current testing of thin-walled tubes.