Femtosecond (fs) broadband vibrational sum-frequency generation SFG) spectroscopy, where infrared (IR) and visible pulses are combined at an interface, has emerged as a powerful method to probe interfacial molecular dynamics. With fs pulses, a range of vibrational transitions can be probed simultaneously and high time resolution can be achieved. We present examples of energy transfer at surfaces studied by combination of fs SFG with ultrafast flash-heating. In these experiments, a Self-Assembly Monolayer (SAM) on metal surfaces adopted as a model system. The metal substrate heated by fs laser pulses, which initiates energy transfer from metal substrate to the SAM molecules on surface, the undergoing response of the surface molecules probed by SFG. By mapping the SFG spectrum with delay time respect to the flash-heating pulse, ultrafast dynamics of energy transfer from metal to SAM molecules, energy flow in surface molecules, and energy dissipation from surface molecules to its surroundings can be derived.