The invention discloses a knife rest mechanism of a glass cutting machine. The knife rest mechanism of the glass cutting machine comprises a rotatable knife rest (3), a fixed knife holder (2) and knife clamping devices (4), wherein the fixed knife holder (2) is used for driving the rotatable knife rest (3) to rotate; and more than two knife clamping devices (4) are arranged on the outer surface of the rotatable knife rest (3) along the rotation direction. Because a rotating hollow spindle of the fixed knife holder drives the rotatable knife rest to rotate and the rotatable knife rest is connected with a plurality of knives through the knife clamping devices, the purpose of automatically changing knives is achieved by rotating the rotatable knife rest, a fixed hollow shaft in the fixed knife holder, a second oil channel of a fixed oil storage disc, a first oil channel of a shell of the knife rest, a third oil channel of a stud and a channel of a taper sleeve connecting shaft form a complete oil changing line, and efficient oil changing can be implemented.