| In view of the lack of current research on concrete mesoscopic model of pebble aggregate, a pebble aggregate model was established based on Bezier curve. The probability distribution characteristics of two important parameters, such as the aspect ratio and radius variability of the real pebble aggregate, were obtained by image processing method. On this basis, the further research on the tortuosity of the concrete mesoscopic model was conducted. The results show that: the Bezier curve can effectively simulate pebble aggregates with smooth edges. the aspect ratio follows the general extreme value distribution, and the values are mostly between 1.0 and 3.0; the radius variability follows the lognormal distribution, and the values are mostly between 0.1 and 0.8; the tortuosity of the concrete mesoscopic model based on pebble aggregates is less than that based on gravel aggregates, and the difference between them increases with the increase of aggregate content.