An image update method, comprising: acquiring, by a render server, a graphics instruction of a virtual machine, wherein the graphics instruction of the virtual machine carries a first graphics update area and graphics update content; determining, by the render server, a type of the graphics instruction of the virtual machine; if the type of the graphics instruction of the virtual machine is a three-dimensional graphics instruction, sending, by the render server, a drawing instruction to a graphics processing unit to perform rendering processing, wherein the drawing instruction carries the three-dimensional graphics instruction, acquiring a rendering image corresponding to the graphics instruction of the virtual machine, and sending a graphics update instruction to a primary surface management unit of the render server, wherein the graphics update instruction carries the rendering image and the first graphics update area; acquiring, by the primary surface management unit, an original primary surface of the virtual machine, synthesizing a new primary surface according to the original primary surface of the virtual machine, the first graphics update area, and the rendering image, and sending an image corresponding to the new primary surface to a client of the virtual machine; and if the graphics instruction of the virtual machine is a two-dimensional graphics instruction, sending, by the render server, a graphics update instruction to the primary surface management unit, wherein the graphics update instruction carries the two-dimensional graphics instruction and the first graphics update area, acquiring, by the primary surface management unit, an original primary surface of the virtual machine, synthesizing a new primary surface according to the original primary surface of the virtual machine, the first graphics update area, and the two-dimensional graphics instruction, and sending an image corresponding to the new primary surface to a client of the virtual machine. acquiring, by a render server, a graphics instruction of a virtual machine, wherein the graphics instruction of the virtual machine carries a first graphics update area and graphics update content; determining, by the render server, a type of the graphics instruction of the virtual machine; if the type of the graphics instruction of the virtual machine is a three-dimensional graphics instruction, sending, by the render server, a drawing instruction to a graphics processing unit to perform rendering processing, wherein the drawing instruction carries the three-dimensional graphics instruction, acquiring a rendering image corresponding to the graphics instruction of the virtual machine, and sending a graphics update instruction to a primary surface management unit of the render server, wherein the graphics update instruction carries the rendering image and the first graphics update area; acquiring, by the primary surface management unit, an original primary surface of the virtual machine, synthesizing a new primary surface according to the original primary surface of the virtual machine, the first graphics update area, and the rendering image, and sending an image corresponding to the new primary surface to a client of the virtual machine; and if the graphics instruction of the virtual machine is a two-dimensional graphics instruction, sending, by the render server, a graphics update instruction to the primary surface management unit, wherein the graphics update instruction carries the two-dimensional graphics instruction and the first graphics update area, acquiring, by the primary surface management unit, an original primary surface of the virtual machine, synthesizing a new primary surface according to the original primary surface of the virtual machine, the first graphics update area, and the two-dimensional graphics instruction, and sending an image corresponding to the new primary surface to a client of the virtual machine.