The influence of angles of inclined cooling plate on cast structure and mechanical properties of cast iron was investigated experimentally in 3.1 wt.% C containing hypoeutectic semisolid cast irons fabricated by flowing the molten melt over the inclined cooling plate and pouring into a preheated permanent mold. The variables used in this study were angles of the cooling plate (5 ~ 15 deg) and the mold temperatures (500~700 deg). The microstructure of resultant specimens were characterized by measuring grain sizes of primary austenite and its solid fraction, using an optical microscope equipped with a digital image analyzer. It was shown that the spherical-like austenite (1.4 aspect ratio) was formed at the cast iron specimens prepared in employing a 10 deg angle of the inclined cooling plate. This was ascribed to the relative extent of duration time of the flowing melt which determine the solidification rate of the melt. The peak hardness and impact values were achieved in the semi-solid cast iron specimen with relatively more spherical austenite. The measured values were approximately 44HRC and 1.71 J/cm2.