The impact behavior between discrete phase and concave-wall was complex and changeable in cylindrical section equipment and pipeline, which directly affected the mass transfer efficiency of inter-phase. In this work, the dynamic characteristic of CCl4 single droplet with iodine containing under water impacting the concave-wall was systematically studied by experiment and image post-processing. The results showed that the settlement velocity of CCl4 droplet under water was relatively stable and only was related to the droplet initial diameter. The process of droplet impacting the concave-wall was divided to five stages, falling stage, spreading stage, relaxing stage, rolling stage, and wetting stage, respectively. The droplets stretched along the circumferential direction of concave-wall and contracted along the normal direction of concave-wall. The effect of the impact angle between droplet and concave-wall θ on the droplet stretching property was greater than the droplet initial diameter and concave-wall curvature radius. The droplet vertically impacted at the lowest point of the concave-wall, then bounced rapidly and contracted strongly when θ=90°. The spreading time was shorter and the deformation rate was the smallest, there was no rolling stage. At the range of θ=100°~150°, the droplet deformation rate increased with the increase of impact angle, the sliding deformation rate was less than the rolling deformation rate. The travel distance, times and duration of droplet oscillation at the concave-wall lowest point increased. At the same time, the oscillation amplitude of droplet velocity increased in the gravity direction. The droplets were mainly sliding and spreading at the range of θ=110°~130°. The phenomenon of droplet rolling along the concave-wall was more likely to occur at θ>130°. The droplet was close to the pure rolling state when θ=154.2°, the droplet diffusing and relaxing stages were very short, the droplet earlier got into the wetting state. The impact angle was increased for the droplet rolling along the concave-wall, effectively reducing the wall adhesion and droplet breakage.