This paper studies the effect of technical parameters of injection molding including the temperature of the regions in cylinder, molding temperature, injection pressure, molding clamp force, injection time, pressure holding time, cooling time, injection velocity, rotation velocity of screw, closing and opening velocity on quality of technical plastic parts. From that point, this paper gives the recommendationsfor manufacturers oftechnical plastic parts. These results obtained from the study and the fabrication of plastic part with high precision at the Nhat Minh company.