Abstract: Taking for example the flawless detection of the imperial tablet of the reign of Emperor Qian Long of the Qing Dynasty unearthed recently for its protection and restoration,the paper introduces a new method of detecting quantitatively fractures and weathering degrees inside stony cultural relics with the ultrasonic detector.This method can not only detect the trend and development degrees of the fractures inside stony cultural relics(e.g.stone Buddha carvings,tablets and pillars) of different ages,but also judge their weathering degrees and intensities according to the ultrasonic characters.In a word,the detector can furnish reliable data for the preservation and recovery of cultural relics.