SEAT BACKREST WITH GOOD SUPPORT EFFECT

Provided in the present utility model is a seat backrest with a good support effect, comprising a seat surface, side struts being vertically secured on both sides of the rear edge of the seat surface, backrest plates being connected to the side struts on both sides by means of springs, and the backrest plates being limited between the side struts on both sides in a back and forth sliding manner; a middle strut is vertically secured in the middle of the rear edge of the seat surface, both sides of the middle strut respectively being provided with a locking mechanism, and the locking mechanisms acting on the backrest plates to lock the backrest plates; also comprising a controller, the controller being externally connected to a power source and being electrically connected to the locking mechanisms; when the user leans back, backrest plates in different positions can move different distances backward according to the differences of the force to which same are subjected, and the locking mechanisms are controlled