The invention relates to a self-blowdown vibration-absorbing foot for a wall-climbing robot, which is characterized in that the device consists of an upper plate component, a lower plate component, a blowdown mechanism, a driving cam, a lathe dog bearing, a cam sleeve, an upper and lower plate connecting piece, a stabilizing ring, a fastening spring, a retaining nut and a blowdown mechanism fastening bolt, wherein the driving cam drives the cam sleeve and the upper and lower plate connecting piece to reciprocate along a guide bar through the lathe dog bearing; air absorption and discharge control of the absorption device is completed through positive and negative rotation of a motor by utilization of an eccentric unilateral bearing; and the stabilizing ring ensures that the overall stability of the robot can not be influenced by self vibration when the absorption device is used as the foot of the robot. The absorption device can be normally operated on the indoor painted metope; and when the absorption device is operated on the ceramic tile wall surface, the positive tensile load can reach 120 newtons, the power consumption is only 2 watts, the deadweight is 300 grams, and the occupied space is phi 120X50. Compared with the prior absorption device, the performance of the absorption device is obviously better.