A vibration-proof fastener post structure includes a body portion having a first end integrally formed with or assembled to a first object; a fastening head portion movably mounted to a second end of the body portion and having a neck portion, which is movably disposed in the body portion for moving in a slideway hole of a second object; and an elastic element movably fitted around the neck portion to push against the body portion. The fastening head portion and the body portion are configured for engaging with and fastening to the slideway hole of the second object. The second object is slidably relative to the neck portion. When the second object is slid to a predetermined position, the fastening head portion and the elastic element, the body portion or the pushing member will engage with the slideway hole of the second object to achieve a vibration-proof fastening effect.