Usually, asphalt mixture is looked on as viscoelastic body. So, author gives time to learning about viscoelastic nature of asphalt mixture. It have a nature of stress relaxation which is different from the elastic body. In order to study this nature, this experiment was performed with a dinamic loading machine of asphalt mixture. This dynamic machine was designed to give a various kinds of stress or strain wave and to measure the resulting strain or stress wave. Sinusoidal, square, triangle and tooth waveforms were obtained from a function generator and this equipment are controlled by a closed loop feed back system. At first, constant rate of strain and constant strain tests are practiced under constant temperature. And the viscoelastic constant of asphalt mixture could be decided from their stress-time relationship. In studying dynamic properties, a stress which varies sinusoidally with time is imposed, and the resulting strain, which also varies sinusoidally but in general is out of phase with the stress, is measured as a function of frequency. In this experiment, the use of square wave strain-time pulse has been discussed.