This paper studies the processing parameters in LED package manufacturing which leads to poor color consistence in the LED packages. With 4 process parameters including die color co-ordinate, dispensing idle time, curing idle time and curing temperature, the critical parameters in affecting the LED package color quality has been investigated by design of experiment. In the analysis of variance, the die color co-ordinate and the dispensing idle time has been found as the critical factors for color derivation from the target, with the later to be the most critical. A regression equation that describes the relationship has been obtained and validated with the measurement data. The equation helps process engineer to design the process window for controllable color variation with production yield improvement. It also helps in die bins selection for a given color reproducibility requirement.