The invention relates to an auxiliary frame assembly for an electric car, and the electric car. The auxiliary frame assembly for the electric car includes an auxiliary frame body; an installation structure for connecting a car body is arranged on the auxiliary frame body; the installation structure includes an installation portion and a boss; the installation portion is connected to the car body;the boss is in the direction perpendicular to a direction from a headstock of the car to a tail of the car, and is higher than the installation portion in the direction of the car body; and the boss is pressed against the car body in the direction from the headstock of the car and the tail of the car. After the auxiliary frame assembly is arranged on the car body of the electic car, the boss limits motion of the auxiliary frame body toward a battery pack under an external force while the electric car is subject to a front collusion. The situation that the auxiliary frame body impacts the battery pack arranged on the car body can be avoided, and the safety and stability of the battery pack can be ensured.