The present disclosure provides an orthogonal codes based code division multiplexing method of performing the code division multiplexing of demodulation reference signals in multiple layers of resource blocks by using orthogonal matrices, the method comprising: changing the order of chips in particular rows of a first orthogonal matrix to obtain a second orthogonal matrix with the changed order of chips; and multiplying the chips in respective rows of the second orthogonal matrix by the demodulation reference signals in corresponding layers of resource blocks correspondingly in the time direction to obtain code division multiplexing signals. The technical scheme of the present disclosure can improve the power jitter situation of downlink signals on the time, thereby the usage efficiency of the power amplifier at the base station side can be improved.