Loop heat pipe (LHP) is an efficient heat transfer devic e for electronics cooling.In order to improve the heat transfer performance of loop heat pipe,the effect of ethanol o n the transfer performance (such as start-up,temperature oscillation and the thermal resistance) of a loop heat pi pe is investigated experimentally. The loop heat pipe with sinter wick and the condenser is an aluminum sun-flower heat sink.The sinter wick provides larger capillary force to get liquid flow back.The aluminum sun-flower hea t sink can make the whole loop heat pipe system more portable,which is better for the loop heat pipe heat sink with different installation conditions. The experimental results show that the start-up characteristic is related to the input heat and the filling ratio, when the input heat increases or the filling ratio is proper,the loop heat pip e could startup successfully;the temperature oscillation is gentle with the input heat increases,but the freque ncy increases with the filling rate increases;there is an optimum filling ratio (60%) at the same input heat w ith the lowest thermal resistance. These results are expected to provide a theoretical reference when loop h eat pipe is applied to electronics for effective heat dissipation.