UTM system was used to test asphalt mixtures dynamic modulus with different sulfur contents（by mass）.The influences of temperature, loading frequency and sulfur content on the viscoelastic properties of asphalt mixtures were analyzed.The results show that the temperature and loading frequency have the same influence on dynamic modulus of both sulfur modified asphalt mixture and conventional asphalt mixture.The effect of sulfur contents on viscoelastic properties of asphalt mixtures is different.A small quantity of sulfur will increase asphalt mixtures viscosity and temperature sensitivity, but a large quantity of sulfur will increase asphalt mixtures elasticity and reduce temperature sensitivity.