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Aimed at three different notches with typical structural features, the stationary flow characteristics were investigated thoroughly and critically. The computational fluid dynamics approach was used to investigate the pressure distributions in notches, and the changing rules of the restriction locations were obtained. After deducing the calculation formulas of flow area, the metering characteristics of notches were studied. Based on the relation of flow rate vs pressure drop characteristic, the discharge coefficient as a function of Reynolds’ number was obtained by using experimental study and theoretical analysis methods. The stable value of the discharge coefficient was also given, and its variation pattern with variable openings was discussed. Based on high consistency between theoretical values and experimental results, the steady flow force and throttling stiffness were investigated, and the results agreed with observed ones were obtained. It was shown that spheroid-notch was applicable under the case of rapid pressure establishing as its discharge coefficient was high when the opening was small, and its flow ability was excellent. Triangle-notch was suitable for the circumstances of high precise control due to high throttling stiffness and smooth increase of flow rate. Divergent U-notch was applied to the conditions of rapid response and stability. The research can be extended to structure optimization and characteristics study of notches, and also provide some