Photoresist monomers, photoresist polymers prepared therefrom, and photoresist compositions using the polymers are disclosed. More specifically, photoresist polymers comprising a photoresist monomer containing fluorine-substituted benzylcarboxylate represented by Formula 1, and a composition comprising the polymer are disclosed. The photoresist composition has excellent etching resistance, heat resistance and adhesiveness, and can be developed in aqueous tetramethylammonium hydroxide (TMAH) solution. And, the present photoresist composition is suitable to form a fine pattern using deep ultraviolet light source such as VUV (157 nm), since the composition has low light absorbance at 193 nm and 157 nm wavelength. wherein, X1, X2, R1, l and m are defined in the specification.