The present application discloses a method and a device for transmitting data based on rate division non-orthogonal multiple access technology applied in the field of communication technologies. The method for transmitting data comprises: obtaining a plurality of terminals and a plurality of transmission parameters of the terminals; dividing the terminals into strong user terminals and weak user terminals and dividing up a signal-to-noise ratio range according to the transmission parameters; determining, according to the transmission parameters, an optimal division factor within the signal-to-noise ratio range; splitting, according to the optimal division factor, transmission power of the terminals into multiple transmission sub-powers; splitting, according to the transmission sub-powers, transmission data of the terminals; respectively modulating and encoding the split transmission data and applying the transmission sub-powers thereto, in which the transmission sub-power of at least one channel of the strong user terminals is applied to transmission data of a weak user terminal; and obtaining transmission data after the transmission sub-powers are applied and performing subsequent transmission thereof in a non-orthogonal manner. The present application improves transmission efficiency between the terminals and base stations, and channel resources are utilized more effectively.