To improve the quantity of data transmission, Arrayed Waveguide Grating(AWG) type Wavelength Division Multiplexer(WDM) have become quite important for improving the quantity of data transmission. In particular, have many advantages in terms of extension to large scale devices, reproducibility, fabrication cost, and hybrid integration with semiconductor devices. This research was concentrated on the developed optimal molding conditions that can reduce the work time, defects and improving the quality of WDM. Finally, Optimum condition of injection were determinated according to Moldflow analysis results.