Abstract: An online electronic whiteboard content synchronization and sharing system includes an electronic whiteboard server and a plurality of clients, wherein an electronic whiteboard is installed in each client. The electronic whiteboard comprises a first layer, a second layer, a third layer and a fourth layer, which are sequentially stacked together, wherein the first layer is used to set a background color; the second layer is used to set a background picture; the third layer is used to draw received drawing data, which is transmitted from a network side; and the fourth layer is used to draw graphics on a local side. By means of the system, drawing data sent from network sides at the same time does not interfere with drawing data on a local side, such that a high real-time performance is achieved.