To address the impact of temperature on the normal operation and service life of high-power electronic components, a circular microchannel heat sink with cones has been designed. The cones are evenly arranged inside circular microchannels, which can change the flow state of the cooling medium in the microchannels and enhance the heat transfer performance. The experimental scheme of the heat transfer performance of microchannel heat sink was designed by an orthogonal test method, and the numerical simulation was carried out by ansys thermal-fluid–solid coupling. Within the test parameters, the inlet pore size, the split outer diameter, and the number of cone columns have effect the temperature of the heat sink base. Further, the inlet pore size and the number of cone columns have a heightened effect on the test results: the base temperature of the heat sink decreases rapidly with the increase in the inlet pore size and the number of cone columns. According to the orthogonal test analysis, the structural parameters of the heat sink were optimized. Under the condition that the other boundary conditions are the same, the temperature of the heat sink substrate obtained by the new factor levels combination is 27.87 °C.