Borehole radar has been applied to test exiting bridge pile foundations in order to improve the interpretation accuracy of borehole radar detection results.The principles of various data processing methods are introduced in this paper.The radar profile effect is compared through example analysis before and after treatment，and the process of data processing is summarized.The appropriate processing parameter is then selected by comparison.Therefore，a reference for borehole radar data processing for detection of exiting bridge piles is provided.