The present invention discloses a method and a device for transmitting an information sequence. The method comprises the steps of: performing phase rotation for a binary sequence, wherein binary values in the binary sequence are elements in a set {a, -a}, a is a complex constant which is not equal to zero, the phase rotation comprises one of the following conditions: performing pi/2 or -pi/2 phase rotation for odd index elements in the binary sequence, and performing 0 or pi phase rotation for even index elements in the binary sequence; performing pi/2 or -pi/2 phase rotation for the even index elements in the binary sequence, and performing 0 or pi phase rotation for the odd index elements in the binary sequence; mapping the binary sequence which has been subjected to the phase rotation to corresponding resources of one symbol, and performing transmission according to a DFT-S-OFDMA mode. In this way, power amplifier efficiency of a transmitter is improved, and detection performance of PD2DSS, SD2DSS and PD2DSCH can be also improved.