Abstract: Influence of nitrile rubber oil resistant compound and Al(OH)₃ flame retardant on damping property of chlorinated butyl rubber base system is investigated by determination of complex loss factor under different frequences. The result indicates that the complex loss factor of the system decreases under 70Hz,200Hz and 400Hz as the amount of nitrile rubber increasing. Al(OH)₃ may improves the damping property of the system and with the amount of Al(OH)₃ increasing the complex loss factor under above mentioned frequences increases to a certain extent, reaches the maximum at mass ratio 4:10 of Al(OH)₃:rubber and then decreases.