A uniform scan coordinate system by using photosensitive element of timing driven is proposed to convert the displacement detection of the object into measured time difference. According to the conversion principle of relative motion coordinate systems of time grating, if the photosensitive element of linear CCD is regarded as a uniform scanning coordinate system and the spatial side by side and timing of mutually staggered on the two linear CCD is regarded as a stationary coordinate system, size and direction of the relative displacement of the object would be made by multiplying time difference variation and scanning speed after the time difference variation of the output electric signal on the different CCD for the same object are measured. With the calibration of the Renishaw laser interferometer for the developed linear CCD time grating sensor, the measurement errors could be controlled within ±2 μm after error correction is made for the effective measurement range of 600.05 mm. This realizes the idea of time measurement space in the field of optical.