Magnetic circuit parts as key components in GDI injector require highly processing technology, but the traditional metal cutting exists the problems of low efficiency, low precision, low material utilization rate and unstable performance, so the metal injection molding technology (MIM technology) was introduced into the GDI injector production. According to the forming characteristics of GDI injector and the performance requirements of the MIM technology, the Fe based nanocrystalline soft magnetic alloy powder Fe73.5Cu1Nb3Si13.5B9 was selected as the molding material of GDI injector magnetic circuit parts, and the structures of the magnetic circuit parts were optimized. Through tracking test of the whole sample production process, the advantages of the MIM technology compared with the traditional technology were analyzed. The MIM technology has advantages in manufacture, physicochemical properties, soft magnetic properties. The characteristics of the GDI injector based on different molding technique were compared by the method of 3D electromagnetic finite element simulation and experiment. The results show that, the simples which were processed by the MIM technology effectively reduce the influence of the skin effect and eddy current loss, accelerate the starting current rise rate, shorten the dynamic response time, increase the dynamic injection quantity and expand the linear range of dynamic fuel injection quantity. The comprehensive performance of GDI injector is improved significantly. 