A distributed speech recognition system and method thereof in accordance with the present invention enables a word and a natural language to be recognized using detection of a pause period in a speech period in an inputted speech signal, and various groups of recognition vocabulary (for example, a home speech recognition vocabulary, a telematics vocabulary for a vehicle, a vocabulary for call center, and so forth) to be processed in the same speech recognition system by determining the recognition vocabulary required by a corresponding terminal using an identifier of the terminal since various terminals require various speech recognition targets. In addition, various types of channel distortion occurring due to the type of terminal and the recognition environment are minimized by adapting them to a speech database model using a channel estimation method so that the speech recognition performance is enhanced.