This study investigates the hydrogen evolution reaction (HER) on various crystal surfaces of zinc anodes using first-principles calculations based on density functional theory. The thermodynamic and kinetic aspects of HER are examined to understand the relative HER activity of different crystal surfaces. The Volmer step is identified as the rate-limiting step for HER on the Zn (002) and (100) surfaces, while the Tafel step governs HER on the Zn (101), (102), and (103) surfaces. The generalized coordination number (CN) of surface Zn atoms is proposed as a key descriptor of HER activity. The flat Zn (002) and (100) surfaces exhibit higher HER activity due to their higher CN, which leads to lower hydrogen adsorption energies. Tuning the CN of surface Zn atoms is suggested as a strategy to inhibit HER on the Zn anode. The findings provide a theoretical basis for understanding and suppressing HER on zinc anodes, which is crucial for improving the cycling stability of aqueous Zn-ion batteries.This study investigates the hydrogen evolution reaction (HER) on various crystal surfaces of zinc anodes using first-principles calculations based on density functional theory. The thermodynamic and kinetic aspects of HER are examined to understand the relative HER activity of different crystal surfaces. The Volmer step is identified as the rate-limiting step for HER on the Zn (002) and (100) surfaces, while the Tafel step governs HER on the Zn (101), (102), and (103) surfaces. The generalized coordination number (CN) of surface Zn atoms is proposed as a key descriptor of HER activity. The flat Zn (002) and (100) surfaces exhibit higher HER activity due to their higher CN, which leads to lower hydrogen adsorption energies. Tuning the CN of surface Zn atoms is suggested as a strategy to inhibit HER on the Zn anode. The findings provide a theoretical basis for understanding and suppressing HER on zinc anodes, which is crucial for improving the cycling stability of aqueous Zn-ion batteries.