The Quadruped walking robot “JINPOONG” is developed to be able to walk in the field which is use to detection, surveillance, reconnaissance, security, and assistance. It can move, carry the luggage of 60kg or more and walk at the uneven terrain such as gravel road and slope of 15 degrees or more. By adjusting the length of the leg caused by the ground reaction force and body posture balance control to the sagittal and lateral plane it is possible to walk stably on the uneven terrain. In this paper, we describe a method for the stable walk on the uneven terrain of JINPOONG and show experimental results about varied terrain.