Thermal performance determines the normal operation of electronic circuits and power devices. The required cooling capacity is always increasing with the abroad application of electronic system. Especially in high frequency and large power fields, the defection of fan-cooled radiator comes out. By comparison, liquid cooling system possesses better heat stability and conductivity, which not only improves the stability of system, but also reduces the working costs greatly. Cooling capacity of heat sink is mainly determined by the inner mechanical structure, it is necessary to study the different influences of related structure, so as to guide the structural design of heat sink effectively. Based on thermal analysis by changing a single structure parameter, the structural influences on thermal performance are discussed, and the acquired conclusions are of great importance in thermal design practice of heat sink.