Based on the structural feature of the linear time grating displacement sensor, the main source for the error of dynamic measurement is proposed. Using grating ruler as a mother, when the linear grating displacement sensor spatial location is the measured value of the grating, grating measurement and linear time grating displacement sensor predicted value is compared. Dynamic measurement error is obtained. The error value is to data truncation error and sampling, abnormal data, then the error value of amplitude spectrum and phase spectrum analysis, so as to the correction of error separation and harmonic correction development of highprecision linear time grating displacement sensor.