Heat dissipation in surface acoustic wave (SAW) devices has never been researched in detail previously. With the arrival of the 5G era, more SAW devices with more complicated structures such as bonding wafers need to be integrated, easily leading to heat accumulation, so investigating heat dissipation in SAW devices is now necessary and urgent. Learning from the thermal-management researches in other fields and considering the mechanism and properties of SAW devices, this work believes that optimizing material design is efficient for heat dissipation enhancement. Therefore, this work for the first time systematically investigates the impacts of material design on heat dissipation and power handling which is significantly influenced by heat dissipation, building up a thermal-management theory for SAW devices based on bonding wafers. This work proposes a theoretical thermal calculation method for SAW devices, building a model and coding a calculation program. This work develops an experimental method by which the impacts of material design on heat dissipation can be deduced from those on power handling, designing and fabricating band-8 duplexers based on bonding wafers with different material designs. This work reveals that SiO2 and epoxy both weaken heat dissipation and impair power handling, while Si, sapphire, and SiC can all be chosen as heat-sink materials. Cost-efficient Si is quite proper for supporting substrates, and metal bumps are effective for thermal dissipation. This work gives guidance on enhancements of heat dissipation and power handling, helping researchers manage thermal properties in SAW devices and promoting the development of 5G communication.