Abstract: Quality inspection of pile foundations，is very important in the field of geotectonic engineering，especially engineering evaluation of integrality and damage degree．Electromagnetic wave computerized tomography (EWCT) is a new geophysics method for quality inspection of pile foundations．The main technological objective of EW CT is to acquire 2D images of defect distribution in the pile foundation and to evaluate the quality of pile foundation．This paper designs and tests the observation system and technique of data collections in EWCT as well as data processing of EWCT to the quality inspection of pile foundations．With a practical engineering example of successful application，the paper illustrates the effectiveness of this method ．In the engineering demonstration，through the field tests data，the author acquire the CT images derived from the data inversion，then combined the result of CT technology and the result of drilling survey data．The comparative result shows that EWCT has the advantages of higher precision and credibility．When the pile foundations have inhomogeneous defects of layers, this method can efficiently and accurately make precise image of the defects distribution between wells．Electromagnetic tomography levels is clear，defects distribution is obvious geologic data，the interior structure and quality qualitative analysis and quantitative analysis． and intuitive．Combining with other engineering of concrete can be evaluated accurately through qualitative analysis and quantitative analysis．