Abstract: We propose a method for multi-scale representation of curve which keeps topological relationship unchanged and elaborates the process of progressive transmission of curve data over the Internet based on this method. Firstly, the importance degree of nodes and the information about public constrain points and monotone chains are stored in a monotonous linear BLG tree structure. Then the multi-scale curve is generated in real time based on this structure and the topological relationship is maintained by an optimized monotone chains intersection algorithm. Finally, the method was used in the experiment of progressive transmission of curve data over the Internet and verified its effectiveness.