The present invention relates to a door hinge assembly and, more specifically, a door hinge assembly which can prevent the phenomenon of closure of an open door by performing a self-stay function, and can improve a worker's or user's convenience and implement a cost saving effect by simplifying the configuration compared to the prior art in which a hinge and a stay are separately provided. To this end, the present invention provides a door hinge assembly comprising: a hinge shaft; a rotary plate which has one side rotatably connected to the hinge shaft and has the other side connected to a door; and a fixing plate which has one side connected to the hinge shaft and has the other side fixed to a door frame which is formed on the wall surface of an inner space that is opened and closed by the door, wherein the upper end surface of the rotary plate is divided into a reference surface and a stepped surface which has a relatively lower height than the reference surface, and a protrusion part which can be mounted on the reference surface is formed on the outer circumferential surface of the hinge shaft which faces the upper end surface of the rotary plate.