A kind of precision bearing surface defects optical test system was established based on machine vision. Image expanding and splicing technology was used to acquire the two dimensional (2DOF) image of bearing with whole profile and no repeat, on this basis, the bearing surface tiny defects detection, defects extraction and classification were carried out. Experimental results show that using this method can quickly and efficiently detect the precision bearing surface tiny defects which are greater than 10 μm; and can accurately classify pits, cracks and scratches of defects. 