This study focused on analysis and experiment of hot extrusion of aluminum and magnesium alloys, an extrusion die with an inclination angle leads to non- uniform velocity distribution at the cross-section of the die, and results in different strain and strain rate distributions. This kind of design can make the grain size at the material surface smaller and get a material with larger surface hardness. This study aims to conduct hot extrusion with different die inclination angles, and obtain a material with gradient micro-structures. At first, die with different inclination angles are designed, and the temperature at the die exit and effective strain, effective strain rate distributions are discussed using the finite element analysis. At last, aluminum and magnesium extrusion experiments are conducted and the micro-structures of the materials are observed to understand the effects of the die inclination angles at 15 degrees on the grain size distribution and hardness test at the cross-section of the material. The grain size is about 17.2£gm at around center of the cross-section and hardness is about 68.2HV. The smallest grain size is 4.1£gm at the edge of the cross-section and the highest hardness is 83.8HV.