The evolution characteristics of the droplets colliding with the wet wall surfaces are essential to the performance of the steam-water separator in the nuclear power plant. When the droplets impact the liquid film with different velocities, the diverse phenomena will occur. The collision characteristics of droplets with the wall surface during the movement are experimentally studied. In the experiment the high-speed camera with a shooting speed of 2000 frames per second is used to obtain the spread process of droplets hitting the liquid film vertically at different velocities. The phenomena of the crown with and without splashing are analyzed. The critical parameters of phenomena are recorded, and the qualitative conditions generated by the three phenomena are analyzed. The critical velocity to generate the secondary droplet is 0.021 m/s and the critical velocity to generate the main droplet is 0.017 m/s when a droplet with a diameter of 3.62 mm hits the liquid film. If the kinetic energy of falling droplets can be reduced, the waste caused by the Worthington jet and splashing droplets can be effectively reduced. The present study can lay basis for the design of the steam-water separator and the space droplet radiator.