The present invention relates to a modified epoxy acrylate and a method for producing the same, a photoresist composition and a method for producing the same, and a transparent photoresist formed from the photoresist composition. The modified epoxy acrylate is an epoxy acrylate modified with phosphate monomer which has a structure represented by Formula I wherein, n is an integer selected from 1˜21, R is a short-chain carboxylic acid ester group having the structural formula  in which p is a bivalent saturated or unsaturated carbon chain having 1˜10 carbon atoms, and the carbon chain is optionally substituted by alkyl, alkenyl, hydroxy, nitro or halogen. Since the phosphate can react with the multi-valence metal in substrates so as to connect the polymer onto the substrates firmly through covalent bonds, therefore the adhesion force is improved significantly and the protective function of the tranparent photoresist is improved accordingly.