Abstract: The rheological property of liquid hydroxy-terminated polybutadiene (HTPB) was studied as a function of shear rate,temperature and its molecular weight. Measurements were made in the temperature from 15 to 70℃ and shear rate range from 0 to 2279s^-1. The flow behavior of HTPB is found to be essentially Newtonian. When bulk vis-cosity is below 1 Pa. sec. and shear rate below 650 s^-1., but it is also a non-Newto-nian under other conditions.The results concerning the relationship between bulk visco-sity and temperature are following the empirical equation:logη_a=A+B/T, when the molecular weight of HTPB is 1,000—5,600.The relation between bulk viscosity and number average molecular weight was established as η_a=2.09×10^-8M_n^2•52 and η_a=1.14×10^-8M_n^2•55 at 20 and 25℃, respectively.