The improved diffractive superresolution element (DSE) is being applied to improve the microfabrication radial superresolution in the two-photon three dimension (3D) microfabrication system, which appeared only a few years ago and can provide the ability to confine photochemical and physical reactions to the order of laser wavelength in three dimensions. The design method of the improved DSE is that maximizi S if the highest limit Mu of the M and the highest limit Gu of the G is set, where reference [1] explained the definition of the S, M and G. Simulation result proved that the microfabrication radial superresolution can be got by the improved optical DSE. The phenomenon can only be interpreted as the intensity of high-order and side of the zeroord erdiffraction peaks have been clapped under the twophoton absorption (TPA) polymerization threshold. In a word the polymerized volume can be chosen because the Mu and the u is correspondingly adjustable, even if the laser wavelength, objective lens and the photosensitive resin is fixed for a given microfabrication system. That means the radial superresolution of the two-photon microfabrication can be chosen.