Droplet dynamics on surfaces under shear flow, which affects the efficiency of water condensate removal in condensation, are significant for investigation. The influencing factors include air velocity, droplet volume and surface wettability. Three smooth surfaces (HI, HO-POTS, and HO-PDMS) and three semi-textured surfaces (HI+SHO, HO-POTS+SHO, and HO-PDMS+SHO) are fabricated. Experiments are performed for droplets with different volumes under different air velocities. A centrifugal fan is used to generate channel flow, and a high-speed camera is utilized to capture droplet behaviors. The results show that motion of droplets with small deformation on smooth surfaces can be divided into two stages (Acceleration and Constant Speed). Critical velocity for the onset of droplet motion, as well as the velocity that droplet can reach at Constant Speed Stage, is affected by air velocity, droplet volume and surface wettability. The mathematical expression of retention force is derived, and forces are calculated to verify the force balances at Constant Speed Stage. Droplet behaviors on semi-textured surfaces are much different from those on smooth surfaces, especially when crossing the boundaries between smooth and textured areas. The HO+SHO surfaces display a better performance of droplet removal compared with the HI+SHO surface.