We developed a multi-reflection data collection method in order to improve the signal-to-noise ratio (SNR) and sensitivity of SFG spectroscopy, which we refer to multi-reflection SFG, or MRSFG for short. To achieve MRSFG, a collinear laser beam propagation geometry was adopted and trapezoidal Dove prisms were used as sample substrates. An in-depth discussion on the signal and SNR in MRSFG was performed. We showed experimentally, with "m" total-internal reflections in a Dove prism, MRSFG signal is ~m times that of conventional SFG; SNR of the SFG signal-to-background is improved by a factor of >m1/2 and <m. MRSFG also improved the SFG sensitivity to resolve weak vibrational signal. Surface molecular structures of adsorbed ethanol molecules, polymer films, and a lipid monolayer were characterized using both MRSFG and conventional SFG. Molecular orientation information of lipid molecules with a 9% composition in a mixed monolayer was measured us-ing MRSFG, which showed a good agreement with that derived from 100% lipid surface coverage using conventional SFG. MRSFG can both improve the spectral quality and detection limit of SFG spectroscopy and is expected to have important applications in surface science for studying structures of molecules with a low surface coverage or less ordered molecular moieties.