The invention provides a method for extending communication capability. In digital communication network, a data on each communication channel is coded according to a first coding method and decoded according to a first decoding method. The method comprises the following steps of: firstly, coding information from a terminal according to a second coding method to obtain a second coding data; secondly, merging the second coding data at least from two terminals into a multiple terminal coding data, wherein multiple terminal coding data quantity is not more than data quantity of one terminal which is coded according to the first coding method; thirdly, taking the multiple terminal coding data as a data transmitted by any one of communication channels in the digital communication network at aninformation receiving terminal; fourthly, dividing the multiple terminal coding data received from the communication channels into a second coding date from different terminals; and fifthly, decodingthe second coding date into a terminal information by a second decoding method corresponding to the second coding method.