The present invention discloses an onboard speech interactive system, which comprises a speech acquisition module, a core speech recognition module, and a speech feedback module, wherein, the core speech recognition module comprises an acoustic model and pronunciation dictionary module, a context irrelevant syntax module, and a path searching module; the acoustic model and pronunciation dictionary module is designed to establish a mapping table related to accent variation characteristic with a statistical algorithm; the context irrelevant syntax module is designed to construct a syntax and rule structure for the natural continuous speech to be recognized; the path searching module is designed to carry out approximate simplification for the observed probability calculation part with the highest amount of calculation. The present invention implements control and operation of the onboard information system by means of natural speech (including command phrases, conjunctions, and continuous speech that follows certain rules), and thereby can enhance driving safety, and implements intelligent man-machine interaction in the onboard information system, independent of driving safety and dynamic performance of the automobile.