The present study is mainly focused on the evaluation of interface reaction between ceramic fillers and phosphate glass matrix for barrier ribs in PDP. The samples were prepared by dry milling for frits with a mean particle size(d50) of 1-2㎛. The frit was mixed with ceramic fillers (Al2O3, ZnO) and was fired at 550°C for 30 minutes. Interface reaction was observed by measuring the weight change of fired samples as a function of immersion time in 90°C de-ionized water and in 60°C acid solution. Fired samples were characterized by differential thermal analyzer, scanning electron microscopy, X-ray diffraction and ion dissolution was analyzed by inductive coupled plasma measurement. The results suggest that properties of barrier rib depend on the crystallization behavior and interface reaction between the fillers and the glass matrix.