Recently, magnesium alloys are often applied in the auto industries and electric appliances. Most of them are manufactured by using some casting methods. But, from the viewpoints of productivity and quality of product, it is easily expected that the development of press forming technology is strongly required along with other metals and alloys. It is therefore important to grasp the plasticity of magnesium alloys. The purpose of this work is to investigate the possibility of press forming on AZ31 magnesium alloy plate. So, the tensile tests were performed to understand its basic material characteristics, and press forming tests were strived to improve its deep-drawability. The results of this study are summarized as follows. From the tensile test, the elongation of AZ31 was about 10% at room temperature, but the elongation increases in increasing temperature and amounts to 80∼90% at 473 K. It was also found that the limit of drawing ratio of AZ31 plate resulted in 3.2 by heating the die at 473 K or above and by cooling the punch at room temperature or below.