||Recently, flexible display have studied to complete a high flexibility and high surface hardness. Organic-inorganic hybrid material is a widely used coating material for flexible display. This show synergistic effect by interaction of the flexibility of organic and the robustness of inorganic. One of organic-inorganic hybrid, silsesquioxane has random, cage, and ladder-like etc, structures. Ladder-like polysilsesquioxane (LPSQ) has excellent mechanical and thermal properties because it has the double-stranded structure backbone of siloxane [Si-O-Si]. In addition, cage-type silsesquioxane (POSS) have a rigid siloxane structure and a nanoscale molecular, so it has high crosslinking-density between molecules, showing excellent mechanical properties. In the study, LPSQ was successfully synthesized with simple sol-gel process. As a result, the LPSQ by added POSS has shown an excellent hardness improvement of 111% (5H) than LPSQ without POSS (4H).