The present disclosure discloses a punching-free mounting assembly for a curtain, a curtain, and a method of installing a curtain; the punching-free mounting assembly for a curtain comprises a mounting seat, a telescopic head, an adjusting plate and an elastic thrust member; the center of the telescopic head is sequentially provided with an outwardly extending threaded column and smooth column. In a natural state, the elastic thrust member squeezes and pushes the mounting seat and the adjusting plate toward two sides, and the limiting part of the smooth column abuts against the outer bottom of the mounting seat, which no longer needs to damage the surface of the wall, and without the requirements of auxiliary tools, a quick and punching-free installation of the curtain is achieved, greatly saving time and effort.