A method and an apparatus for interlace scanning video signal frequency multiplication are provided. The method includes the following steps: first, removing a part of a first vertical synchronous signal (V-sync signal) which is asynchronous with a first horizontal synchronous signal (H-sync signal); next, capturing a first field and a second field from an interlace scan video signal according to the first V-sync signal obtained in the previous step; performing a frequency multiplication on a frame made up by the first and second fields, and producing a second V-sync signal and a second H-sync signal; finally, compensating for the second V-sync signal on a border between two fields of the frame after the frequency multiplication according to the second H-sync signal. Thereby, the method can be used to perform frequency multiplication using a line buffer instead of a frame buffer, to output through interface scanning without sacrificing image quality.