Disclosed is photoresist using dioxaspiro ring-substitued acryl derivatives, represented by the following chemical formula I or II. As matrix polymers, homopolymers of dioxaspiro ring-substitued acryl monomers or their copolymers with acryl monomers are provided. The deprotection of the dioxaspiro rings from the matrix polymers, usually accomplished by the action of a photoacid generator, causes a great change in the water solubility of the matrix, thereby allowing the matrix to be used for the photoresist required to have high sensitivity, resolution and contrast.