The invention relates to a sliding door for a vehicle. The sliding door comprises a vehicle door outer plate 1 and a vehicle door inner plate assembly. The vehicle door inner plate assembly comprisesa vehicle door inner plate 2 and a strip-shaped profile anti-collision beam 13. The profile anti-collision beam 13 is transversely arranged between the vehicle door inner plate 2 and the vehicle doorouter plate 1. The profile cavity section of the profile anti-collision beam 13 is of a flexible structure. The flexible structure is used for absorbing side collision energy through deformation of the flexible structure when the vehicle door collides. The sliding door for the vehicle is good in side collision energy absorbing effect, the side collision safety of the vehicle door is greatly improved, and the riding safety of people in the vehicle is guaranteed.