The invention relates to an increasing and decreasing hydraulic support for a mechanized mining working face of a thin coal seam. The increasing and decreasing hydraulic support comprises a lifting support and a waste edge support, which are mutually connected through a pin shaft, and the lifting support and the waste edge support are arranged in a crossheading track in a slidable manner from front to back along the propulsion direction of the working face; and the lifting support comprises a base, a top beam, upright posts, a shield beam and a connecting rod, wherein the top beam and the base are in hinge joint by the upright posts, the shield beam and the base are in hinge joint through the connecting rod, the back end of the top beam is hinged with the front end of the shield beam, thetop beam is an integral top beam, the upright posts are hydraulic telescopic upright posts, and the upright posts comprise a front upright post and a rear upright post. The increasing and decreasing hydraulic support has the beneficial effects of having the function of adjusting the height, solving the height difference between a baseplate of the working face and a crossheading baseplate, greatlyimproving the supporting effect and the safety coefficient and being suitable for variation requirements of coal seams in different sections.