Seat back cushion capable of being placed stably

The utility model discloses a stably placed seat back cushion, which comprises a back cushion, a mounting plate is fixed on the surface of one end of the back cushion, two groups of sleeves are fixed on the surface of one end of the mounting plate, a mounting block is arranged between the two groups of sleeves, the mounting block is fixed on the surface of the mounting plate, an ejector rod is arranged in the sleeve, and the ejector rod is fixed on the surface of the mounting plate. A top seat is fixed at one end of the top rod, and a rough surface magic tape is fixed on one side of the outer wall of the top rod; according to the back cushion, the sleeve, the ejector rod and the ejector seat are designed, the ejector rod is adjusted in a sliding mode in the sleeve, then the distance between the ejector seat and the mounting plate fixed to the surface of the back cushion is changed, the using thickness of the back cushion can be adjusted, the using range is wider, and the using cost is reduced; the thorn-face