With the continuous increase in power density of electronic devices, traditional cooling methods have gradually shown their limitations. Microchannel heat sinks (MCHSs) have enormous potential in thermal management for electronic devices due to their excellent heat dissipation performance. To improve the flow and heat transfer performance of MCHSs, a numerical study was conducted on 56 types of wavy microchannel heat sinks with manifolds and secondary channels composite (WMCHS-MSCs). The results indicate that compared to the original manifold wavy microchannel heat sink (MWMCHS), the optimal WMCHS-MSC increases the thermal enhancement factor by 45.1 % when the inlet volume flow rate Q = 1.0 x 10(-6) m(3)/s. At the same time, the overall thermal resistance, the maximum temperature difference on the bottom wall, and the pressure drop of the optimal WMCHS-MSC are reduced by 7.6 %, 21.9 %, and 10.6 %, respectively. Compared to the original MWMCHS, the increase in Q for WMCHS-MSCs results in an overall trend of increased thermal performance, decreased temperature non-uniformity and hydraulic performance, and initially increased and then decreased overall performance. The flow field distribution of the secondary channels of WMCHS-MSCs intuitively demonstrates the improved hydraulic and thermal performance brought about by disrupting the thermal boundary layer and mixing the flow. The study presents a novel approach for the design of wavy MCHSs, potentially paving the way for enhanced thermal management solutions in electronic devices.