The invention provides an efficient frequency division multiplexing transmission peak-to-average power ratio reduction method combining orthogonal transformation and non-orthogonal processing, relates to transmission systems and technologies in the technical field of wireless communication and aims to reduce the peak-to-average power ratio at a sending end of a system to a certain extent in a symbolic orthogonal transformation way to solve the problem that the sending end of the efficient frequency division multiplexing transmission system adopting a non-orthogonal carrier has a higher peak-to-average power ratio. According to the method, transmission symbols are generated firstly according to efficient frequency division multiplexing symbol generation principle, and then an orthogonal processing module is further added to the sending end of the system, so that the peak-to-average power ratio at the sending end of the system is reduced. The efficient frequency division multiplexing transmission peak-to-average power ratio reduction method can be applied to new-generation ground, no-load and satellite communications and can solve the problem of spectrum resource scarcity in the future to a great extent, and simulation results prove that the peak-to-average power ratio of the transmission system subjected to orthogonal transformation processing is lower than that of the traditional efficient frequency division multiplexing system.