The present disclosure provides a hydrogen evolution electrode and a preparation method thereof. The preparation method includes the following steps: providing an electrolyte including Co(NO.sub.3).sub.2.Math.6H.sub.2O with a Co(NO.sub.3).sub.2 concentration of 0.005 mol L.sup.1 to 0.015 mol L.sup.1, MnCl.sub.2.Math.4H.sub.2O with a MnCl.sub.2 concentration of 0.005 mol L.sup.1 to 0.01 mol L.sup.1, KCl with a concentration of 0.003 mol L.sup.1 to 0.008 mol L.sup.1, and CH.sub.3CSNH.sub.2 with a concentration of 0.04 mol L.sup.1 to 0.06 mol L.sup.1; adjusting the electrolyte to a pH value of 6 to 7; providing a cathode in the form of a substrate; and conducting electrolysis in a cyclic voltammetry mode, thereby preparing the electrode for hydrogen production by water electrolysis through electrochemical deposition of a Co.sub.9-xMn.sub.xS.sub.8 nanosheet catalyst on the cathode substrate, where 1X7.