Octa-(dinitrophenyl) silsesquioxane (ODNPS) with the yields of 91% and 86% was synthesized by two nitration routes respectively. The composition and structure of the products were characterized by FTIR,²⁹Si NMR,XRD,etc. The results show that the one-step nitration produce octa (2,4-dinitrophenyl) silsesquioxane in major,and the two-step nitration give octa (3,5-dinitrophenyl) silsesquioxane and octa (2,4-dinitrophenyl) silsesquioxane. TGA test of the ODNPS shows that it detonates at 393 ℃. The volume of the released gas was 0.13 mL·g^-1·48 h（100 ℃） in the thermal stability test in vacuum. Impact sensitivity H₅₀ (specific height) was 30.7 cm using 10 kg drop hammer. At 5 MPa,the burning rate of the pressed ODNPS pellets was 4.42 mm·s^-1 with density of 1.85 g·cm^-3 by a burning rate measurement system with real time line scan camera. These indicate that ODNPS is a thermal stable energetic materials.