The invention discloses an all-terrain four-wheel-drive cross country vehicle chassis and a vehicle thereof. The all-terrain four-wheel-drive cross country vehicle chassis comprises a front axle, a rear axle, a back axle, a front connecting shaft, a rear connecting shaft and an adjuster, the front axle is connected with two front wheels, the rear axle is connected with two rear wheels, the back axle is respectively connected with the front axle and the rear axle through a first H-shaped swing frame and a second H-shaped swing frame, and comprises a plurality of rectangular supporting frames in mutual connection, the rectangular supporting frames are used for connecting a frame, the adjuster arranged between the front connecting shaft and the rear connecting shaft is used for adjusting four driving wheels of the front axle and the rear axle to adapt to the height of the ground, the front connecting shaft and the rear connecting shaft penetrate through the front and rear of each supporting frame in the front direction and the rear direction of the vehicle respectively, the front connecting shaft is connected with the first H-shaped swing frame, and the rear connecting shaft is connected with the second H-shaped swing frame. By the aid of the chassis, when the vehicle runs on road surfaces with extremely large height difference, the height of each wheel can be adjusted automatically to adapt to the uneven ground.