<p>In order to solve the heat dissipation problem of square electronic components, a snowflake fractal bionic microchannel radiator is designed based on the fractal structure, the channel width is changed during the fractal process, and the secondary flow channel is introduced. The effects of channel layout, secondary flow channels, and nanofluids on flow resistance and heat dissipation of microchannels were analyzed. The simulation results showed that the primary fractal microchannel (structure I) has better heat dissipation, more uniform temperature distribution, and lower temperature than the distributed microchannel (contrast structure), and the comprehensive performance index can achieve 2 approximately. The newly designed snowflake fractal bionic microchannel (structure II) exhibits superior heat transfer performance and a reduced pressure drop compared to the original fractal microchannel (structure I). The Nusselt number can be enhanced by 14.4% approximately, while the pressure drop can be decreased by 12.65%. In addition, the introduction of nanofluids has further enhanced heat transfer. The reduction in the width of the branch channel in the fractal process and the combination with the secondary flow structure can markedly improve the flow dynamics and thermal performance within microchannels, which has a good application prospect in the thermal management of electronic components.</p>