The invention provides a vinyl ether group-containing copolymer, preparation process and use thereof. The copolymer comprises of the structural units represented by the following general formulae I, II and III, wherein, R1 is O or HN, R2 is an alkyl group with a carbon atom number of 1-4, cyclohexyl or a group represented by the following general formula IV (m represents a positive integer of 1-3), n is a positive integer of 1-4, the molar numbers of the structural units represented by the general formulae I, II and III are x, y and z, respectively, and x:y:z=3-8:1-4:1-5, the weight average molecular weight of the copolymer is 5000-20000. A color light blocking agent added with the copolymer can increase sensitivity. Furthermore, the copolymer has solubility in an alkaline solution, and thus, the color light blocking agent added with the copolymer has a superior developing property.