The invention provides a rear suspension rocker arm mounting structure of an all-terrain vehicle. The rear suspension rocker arm mounting structure comprises a frame, a rear suspension arranged at the rear end of the frame and a rim support connected with the rear suspension. The rear suspension rocker arm mounting structure further comprises rear rocker arms which are located at the two sides of the frame and used for connecting the front end of the frame to the rim support. A front supporting base used for erecting the rear rocker arms is arranged at the front end of the frame. An adapter arranged in a first direction with the rotating direction swinging along the upper portion and the lower portion of the frame and in a second direction steering along the left side and the right side of the frame is disposed between the front supporting base and the rear rocker arms. The adapter used for supporting the front supporting base and the rear rocker arms is arranged between the front supporting base and the rear rocker arms, the adapter rotates up and down around the front supporting base by the rear rocker arms so as to support the frame, the rear rocker arms are used for driving the rim support to swing left and right, auxiliary steering in the rear wheel proceeding direction is achieved, and therefore handling performance of the rear suspension of the all-terrain vehicle is improved, and the control needs of the all-terrain vehicle on the complicated road condition are met. The invention further provides the all-terrain vehicle.