As a widely used pulse encoding technique in the full-digital transmitter, the DSM (Delta-Sigma modulation) can obtain a better performance by increasing the quantizer’s levels. But the multi-level DSM output cannot drive the switching amplifier directly due to the structural restriction of switching amplifier in full-digital transmitter. By using the area equivalent theory and non-uniform quantizing technique, a novel pulse encoding strategy for switching amplifier was proposed and analyzed. The theoretical analysis and simulation results reveal that the pulse output created by the novel pulse encoding strategy gives rise to a much better in-band SNR(signal noise ratio) and coding efficiency performance compared to the traditional 2-level output.