Visual inspection samples of seeding shaft of air blowing precision seeder were got by CCD camera, rotational speed serials were obtained by image processing, whose characteristic was analyzed based on which rotational speed of seeding shaft was investigated through timing analysis. Based on the speed serial data, the auto-covariance function, autocorrelation function and partial autocorrelation function were calculated, and the AR model was selected for analysis of speed serial. The fitted and residual serials were obtained using the actual serials and the AR model (under 45 r/min for example). Through fitting analysis of the residuals and the model, the calculated maximum of residuals is 19.920 6, and 83.83% of the residuals were within ± 6.912 312 r/min, which is the allowed value range; the fit of the model was 74.631 2% with standard deviation of 0.050 136. The model’s coefficients were 16.805 28 at the significance level of 0.000 by t-test.