A radiation pattern insulator and an antennae system thereof are proposed. The radiation pattern insulator includes a dielectric substrate and a plurality of radiation pattern insulation elements. The dielectric substrate allocated between a plurality of antennae includes a top surface and a bottom surface, and a normal direction of the dielectric substrate is substantially perpendicular to propagation directions of electromagnetic waves radiated from the antennae. In addition, the radiation pattern insulation elements are allocated on the top surface or the bottom surface of the dielectric substrate, or alternatively, all allocated on the top surface and the bottom surface.