Abstract: To meet the requirement of adhesion detection on the surface of extremely weak gravitational small celestial bodies, a three-legged detector attachment buffer system was designed, and a stability analysis of the attachment process was carried out. In order to achieve stable attachment to the surface of the small body without rebound in a very weak gravitational environment, a two-stage buffer system was designed considering with the error of landing speed and inclination angle taken into account. The energy consumption of the hook and loop fastener and the crushing energy absorption of the aluminum foam were used to reduce the influence of the contact collision process on the stability of the detector. The multi-body system dynamics model of the detector and the contact collision dynamics model of the detector footpad-granular medium were established. Based on the joint simulation of multi-body dynamics and discrete element, the motion law of the detector under different landing inclination angles and speeds was obtained. The results show that the two-stage buffer system has a good buffer energy absorption effect, which can effectively prevent the detector from rebounding, slipping and overturning. The detector can be stably attached to the surface of the small celestial body within a certain inclination angle and velocity range. The research results can provide technical support for the landing scheme design of small celestial body exploration missions in the future.