The invention relates to an automatic-driving low-speed sweeping vehicle positioning method based on tire radius self-adaptation. The method comprises the following steps that: step one, according toa GNSS state flag position of a GNSS state determination sub module, a vehicle heading angle estimating module carries out calculation to obtain a current heading angle psik; step two, a tire radius estimation module estimates a wheel radius by using Kalman filtering to obtain a tire radius estimation value r; and step three, a position estimation module carries out online real-time estimation ona vehicle location according to the tire radius estimation value r, a wheel speed signal omega measured by a wheel speed sensor, and the current heading angle psik obtained by a sensor signal processing module to obtain a vehicle position estimation value. Compared with the prior art, the provided method has advantages of low cost, great easiness in implementation, accurate position estimation, strong robustness and the like.