As a new imaging technology, photoacoustic tomography (PAT) has attracted more and more attention in biomedical imaging due to its unique multi-scale imaging abilities of label-free, high resolution and high contrast, and has been rapidly transformed into clinical trials. Benefitting from the rapid development of ultrasonic detection technology and laser technology, the PAT system has gradually achieved real-time, large field of view, high resolution and high penetration depth of tissue structure and functional imaging. In this paper, we mainly summarize the advances of the circular array PAT system in biomedical imaging and the problems it faces in preclinical and clinical practices.