PURPOSE: A novel silicon compound applied to organic layer of organic light emitting device is provided to improve thermal stability, luminous efficiency, current efficiency, and power efficiency. CONSTITUTION: A novel silicon compound is denoted by chemical formula 4. In the chemical formula 4, n is integer of 1-5, and R1 to R4 are independently hydrogen, alkyl of 1-30 carbon atoms, alkenyl of 2-30 carbon atoms, aryl of 5-30 carbon atoms, hetero aryl of 5-30 carbon atoms, aryloxy of 5-30 carbon atoms, alkyloxy of 1-30 carbon atoms or heterocycloalkyl of 5-30 carbon atom. The organic light emitting device comprises anode, cathode, and one or more organic layer between the anode and cathode.