The invention discloses an optoacoustic/ultrasonic dual mode endoscope based on piezoelectric micromachined ultrasonic transducer arrays. The optoacoustic/ultrasonic dual mode endoscope includes a piezoelectric micromachined ultrasonic transducer (PMUT) array probe (2), a PMUT array element (1), an integrated circuit (3), a plane lens (4), a condenser lens (6), an optical fiber coupling collimator (7), a single-mode fiber (8), an optical fiber FC/APC connector (9), an optical fiber (10), a signal line (11) and an housing (12). The optoacoustic/ultrasonic dual mode endoscope is characterized in that, the piezoelectric micromachined ultrasonic transducers are adopted, the transducers and the integrated circuit are good in compatibility during manufacturing process, and the transducers are easy to form an array; transducer arrays are adopted, the endoscope does not need to rotate, the imaging speed is raised, real time imaging is achieved; and the multiple transducer arrays can effectively raise the signal to noise ratio of a signal, deep imaging through focusing and scanning is achieved. The optoacousitc/ultrasonic dual mode endoscope can be widely applied to fields of medical endoscopes and industrial flaw detection, and particularly has great application value in in-vivo scar tissue identification, assessment of damage of ablation of tissue, atherosclerotic degree assessment and the like.