LED industry is viewed as one of the most potential industry in recent year. The main reason is that everyone expects LED could get into the lighting and become a brand new light engine. High efficiency, fast turn on/off, longer lifetime than other light engines and free-mercury are the advantages of LED。 However, in addition to the big problem -“radiating”, the main defect of LED is uneven brightness and much higher cost than other light engine, especially in lighting. The main purpose of this research is to investigate the feasibility of using silicone oil for helping heat dissipation of a LED fixture, and to compare with the solid and liquid gel. This research used CFD simulation software to analyze the influences of heat on LED fixture parameters, and conducted experiments to verify the analysis results.