A signal processing circuit is provided. The signal processing circuit, adjusting a received radio frequency (RF) signal according to a gain, and generating a digital signal accordingly, the signal processing circuit including a signal analysis circuit, for analyzing the digital signal to generate the gain, determining whether the received RF signal is a target signal, and generating a reference value according to the digital signal, and a baseband circuit, for performing a carrier frequency offset (CFO) compensation to the digital signal according to the reference value, wherein, the reference value is generated while the signal analysis circuit is determining whether the received RF signal is the target signal.