The theoretical and experimental studies of heat flow control on the microscopic scale are reviewed. We focus on the latest developments in recent years of heat flow control using the temperature dependent power spectra of nonlinear materials. It has been shown that the models describing microscopic heat control devices, such as thermal diodes, thermal transistors and thermal logic gates, are all feasible. In principal, we can not only rectify, switch and modulate heat flow created by phonons, but can also perform basic logic calculations by heat. This research will have wide applications in energy saving and environment protection.