Abstract: How to detect and remove unwanted asperities is a critical problem in the dynamic measurement Measurement of discontinuous curves is the dynamic measurement of discrete points,and results frequently in unwanted asperities.Meanwhile,the measurement sample is not big.Based on the features of the grey theory,a modified Grey Model is introduced to approach the measurement data.Combined with the robust minimum deviation principle,a method using grey theory to detect unwanted asperities in the dynamic measurement is studied.All the equations and the distinguishing criterion are given.