The invention provides a longitudinal speed estimation method and system for an all-wheel-drive electric wheel automobile, and belongs to the field of automobile dynamics control. The method and system are used for estimating the longitudinal speed of the all-wheel-drive electric wheel automobile, and the all-wheel-drive electric wheel automobile is a pure electric automobile with all wheels driven by wheel hub motors directly; the estimation method comprises the following steps of effective wheel screening, longitudinal acceleration signal preprocessing and longitudinal automobile speed estimation; and the system comprises an effective wheel screening module, a longitudinal acceleration signal preprocessing module and a longitudinal automobile speed estimation module. According to the longitudinal speed estimation method and system for the all-wheel-drive electric wheel automobile, the wheel motion state and the validity of the rotating speed information thereof is taken into consideration, the longitudinal acceleration information is fused, and the estimation of the longitudinal speed of the automobile is realized; and the method provided by the invention weakens the dependence on the precision of a dynamic model, and has strong real-time performance and high performability.