Abstract: To reasonably characterize the dispersion of measurement values and determine the validity of measurement results, inspection and testing institutions should develop and implement measurement uncertainty assessment procedures to ensure accurate assessment when needed. When evaluating measurement uncertainty, factors that affect uncertainty should be fully considered, corresponding mathematical models should be established, and the uncertainty components caused by each factor should be accurately calculated. Then, the composite standard uncertainty and extended uncertainty should be comprehensively calculated, and the final result should be provided. Finally, taking the commonly used concrete carbonation depth detection and foundation pile defect depth detection in construction engineering inspection as examples, the evaluation method of measurement uncertainty is practically applied, and relatively accurate measurement results are obtained.