The quadruped walking robot “JINPOONG” is developed to be able to walk in the field which is used 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. To the legged robot walking stable, when an external force is applied to the body, the posture control is necessary to maintain stability. In this paper, we describe a method for the stabilization posture of JINPOONG and show experimental results about the external force.