Dielectric properties of resist materials such as dielectric frequency dispersion, permittivity and dielectric loss tangent, which should be optimized in structural material designing, are characterized. Dielectric properties of resist materials are characterized by traditional capacitance method in the frequency range of 10mH to 5MHz. The relative dielectric constant and loss tangent from dry film resist (DFR) at 1MHz can be determined to be 3.63 and 0.0744. The Cole-Cole plot is employed to determine a dielectric relaxation time of dipole moment in polymer structure. The relaxation time of DFR film can be determined to be 12.1s. The validity of dielectric properties of DFR film as a structural material is discussed.