Hot runner board is the main component of hot runner system in plastic injection mould. The uniformity of its temperature distribution has an important effect on the entire hot runner system and the injection molding product's quality. Taking the LED TV back cover as an example, the basic structure of the hot runner board was designed and its temperature field distribution during the heating process was also studied. Based on the problems of bad uniformity of temperature distribution appeared in the primary finite element analysis results, an optimization design for the layout of the electric heating wire inside the hot runner board was carried on, and the hot runner board structure which had  uniform  temperature distribution was obtained. Applying the hot runner board structure obtained to the hot runner system's design and the project practice，superior quality products were got.