The invention relates to an automobile rear side window area reinforcing structure and an automobile. The automobile rear side window area reinforcing structure comprises a rear side wall inner plate, a rear wheel cover outer plate and a D pillar reinforcing part, wherein a rear side window is arranged at the upper part of the rear side wall inner plate, a C pillar inner plate is formed on the rear side wall inner plate and located on the front side of the rear side window, a reinforcing part assembly is overlapped on the surface, facing the exterior of the automobile, of the rear side wall inner plate, and a cavity reinforcing structure is formed in reinforcing part assembly on the rear side wall inner plate, the reinforcing part assembly comprises a first vertical extending section overlapped on the C pillar inner plate, a transverse extending section extending backwards from the lower end part of the first vertical extending section as well as a second vertical extending section extending downwards from the transverse extending section, the transverse extending section is arranged along the lower edge of the rear side window, the rear end part of the transverse extending section is overlapped on the D pillar reinforcing part, and the lower end part of the second vertical extending section is overlapped on an outer plate of the rear wheel cover outer plate. Excessive increasing of dead weight of the automobile is avoided while the rigidity of the rear side window area is improved and vibration transmission of back doors and vibration transmission of rear wheels are inhibited.