Effects of ingate velocities and the morphology of α-particles on feeding behavior of thin plate were investigated in rheo-diecasting with H-NCM semisolid. In order to acquire various morphological characteristics, three kinds of semisolid, which had different casting parameters, were prepared. In this study, we found that the range of ingate velocity which could achieve laminar flow in thin plate was from 3.88m/s to 6.47m/s. In this range, however, the laminar flow length and the total flow length showed different results according to the characteristics of semisolid. Although the semisolid had high globularity the semisolid which had larger α-particles than 100 showed unstable feeding behavior in the range of stable ingate velocity.