The present application provides a noise shaping circuit including a first modulation unit, configured to generate a first digital output signal according to a first digital input signal, the first modulation unit comprising a first quantizer; a first subtractor, coupled to an input terminal and an output terminal of the first quantizer, configured to generate a first quantization noise; and a second modulation unit, configured to generated a second digital output signal according to a second digital input signal, wherein the second digital input signal is related to the first quantization noise; wherein the noise shaping circuit generates an overall analog output signal according to the first digital output signal and the second digital output signal.