Based on simulated rainfall experiment,hydraulic properties of shallow flow in the coarse sediment region in the middle reaches of the Yellow River were studied. The following results were obtained:(1) Shallow flow velocity increased with rainfall process under different rainfall intensities and slope gradients and it can be described with logarithmic equation. Shallow flow velocity was positively related to rainfall intensity and slope gradient. (2) The averaged shallow flow depth increased steadily with rainfall intensity under different slope gradients and it can be described with power equation. The averaged shallow flow depth was negatively related to slope gradient. (3) Under different rainfall intensities and slope gradients,Reynolds number of shallow flow increased with rainfall process. The influence of rainfall intensity on Reynolds number was more significant than slope gradient. Shallow flow was not the traditional laminar flow but in the state of instability. Froude number increased steadily with rainfall process,with the number being above 1. The influence of slope gradient on Froude number is more important than rainfall intensity. Shallow flow in the experiment was in the state of supercritical flow. (4) The resistance coefficient of shallow flow decreased with rainfall process under different rainfall intensities and slope gradients.