The image photoacoustic tomography (PAT) is constructed through photoacoustic waves emitted from sample after absorbing light energy. The ultrasound signals are obtained by ultrasound transducers and sent to a multi-channel data acquisition (DAQ) system. To decrease the cost in DAQ, a 4-to-1 circuit module is proposed by fusing four channels into one signal employing frequency-division multiplexing (FDM). After the modulated signal’s acquisition, the original signal can be recovered through bandpass filters and associated demodulation algorithm. We have performed imaging experiments and proved the feasibility of this module in the PAT system.