Due to the low material strength and rigidity of the plastic-steel window, although it is reinforced by processing lining steel, the wind-pressure resistance and water-tightness of the plastic-steel window are about two grades lower than that of the aluminum window. Moreover, since the lining steel of the plastic-steel window is not connected to a complete frame system at the corners of the inner cavity of the plastic-steel window profile, the welding corner strength of the plastic-steel window of the window frame, the four corners of the fan and the t-point point is relatively low.