The invention relates to a quick downloading method for large-data documents based on a broadcasting television network and a communication network. The method comprises the steps of: (1) connection: accessing a PC terminal into a broadcasting television network through a set-top box, wherein the terminal of the set-top box is connected with a front servicing device through the broadcasting television network and the communication network, a downloading customer terminal is arranged in the PC terminal, the front servicing device comprises an user accessing managing submodule, a content managing submodule and a content distributing submodule, the content managing submodule stores document resources, and the content managing submodule is connected with an internet; (2) service requesting; (3) service responding; and (4) receiving: receiving the signal containing documents from the broadcasting television network by the set-top box, processing the signal and then sending the signal to the PC terminal. The invention has the advantages of simple and compact structure, low cost, simple realizing principle, easy implementation, great enhancement of downloading speed, and the like.