Asphalt and other organic compounds form an anisotropic structure in lithification. Its product is mesophase which has excellent property and low cost so that it has been widely used in carbon fiber, carbon foam, needle coke and lithium ion secondary battery and many other areas. It can be said that the studies of preparation and structure of anisotropic mesophase of coal asphalt have significance to process improvement and cost savings in these areas. This research carries out an in-depth study in this regard. The selected coal asphalt is used as the raw material to analyze the influence of constant temperature and thermal polymerization temperature to the softening point, yield, group composition and optical microform. The experimental results show that coal asphalt turns into mesophase pitch with softening point of 312? and yield of 79.1% if it is kept in a constant temperature of 420? for 5 hours. However, it turns into mesophase pitch with softening point of 305? and yield of 81.4% if it is kept in a constant temperature of 400? for 8 hours. It shows that high-quality mesophase can be obtained with scientific control of the duration of constant temperature and the thermal polymerization temperature.