The invention relates to the field of substrate glass plate processing, and discloses a glass grinding machine and a grinding head assembly thereof. The glass grinding machine comprises a machine frame, and the grinding head assembly comprises a grinding wheel unit and a feeding driving unit, wherein the grinding wheel unit comprises a grinding wheel and a grinding head motor used for driving the grinding wheel to rotate around the axis, and the grinding wheel unit is installed on the feeding driving unit so as to be driven by the feeding driving unit to move in the axis direction of the grinding wheel; and the grinding head assembly further comprises a grinding angle adjusting unit which comprises an angle adjusting plate, a sliding wheel assembly and fastening parts, wherein one surface of the angle adjusting plate is installed on the machine frame, an arc-shaped adjusting track is formed on the other surface of the angle adjusting plate, the sliding wheel assembly comprises a sliding wheel and a fixed end, the fixed end is installed on the feeding driving unit, the sliding wheel is installed in the adjusting track in a sliding manner, and the angle adjusting plate and the feeding driving unit are detachably fixed with the fastening parts.