The invention discloses a back-row seat framework made of hybrid materials for a passenger car. The back-row seat framework made of the hybrid materials for the passenger car aims to achieve the purposes that the impact resistance is high enough and low weight is achieved. The back-row seat framework made of the hybrid materials for the passenger car is composed of a first seat framework body and a second seat framework body. The first seat framework body is composed of a first rectangular frame and a first framework back board assembly, and the first framework back board assembly is installed in the first rectangular frame and is integrally connected with the first rectangular frame. The second seat framework body is composed of a second rectangular frame and a second framework back board assembly, and the second framework back board is located in the second rectangular frame and is integrally connected with the second rectangular frame. The first rectangular frame and the second rectangular frame are both folding plate uniform-section shell structural pieces, and reinforcing ribs are arranged on the identical sides of a first framework back board (5) in the first framework back board assembly and a second framework back board (67) in the second framework back board assembly. The first seat framework body and the second seat framework body are arranged on the passenger car side by side, and the horizontal distance between the first seat framework body and the second seat framework body is 32 mm.