A combinatorial polymerized-complex method was adopted in order to search for new Tb3+ activated green phosphors based on the CaO-Gd2O3-Al2O3 ternary system. In an attempt to apply newly found phosphors to the plasma display panel, a combinatorial screening was carried out in terms of the photoluminescence (PL) at the vacuum ultraviolet excitation (147 nm). As a result, the optimum composition range was determined as 0.2 < x < 0.25, 0.25 < y < 0.3, and 0.45 < z < 0.5 for Ca-x(GdTb)(y)AlzOdelta. We found that the samples in the optimum composition range consist of CaGdAlO4, CaGdAl3O7, and GdAlO3 phases. The mixed compounds showed a much higher PL efficiency than did any of the constituent compounds.