We report a method for synthesizing a plasma-treated sponge-like NiAu nanoalloy to enhance the hydrogen evolution reaction (HER) performance. First, an as-prepared sponge-like NiAu nanoalloy is obtained by using NaBH4 to reduce a NiCl2 and HAuCl4 mixture without using any surfactant. Second, this as-prepared sponge-like NiAu nanoalloy is treated by argon plasma under atmospheric pressure with a treatment time of 15 min to obtain the final plasma-treated sponge-like NiAu nanoalloy. The HER electrocatalytic performance of the plasma-treated sponge-like NiAu nanoalloy is then investigated in 0.5 M H2SO4 electrolyte. From the results, the plasma-treated sponge-like NiAu nanoalloy exhibits enhanced HER performance compared to the as-prepared sponge-like NiAu nanoalloy due to the exposure of more active/edge sites. The overpotential at a current density of 10 mA.cm(-2) of the plasma-treated sponge-like NiAu nanoalloy (88 mV) is lower than that of the as-prepared sponge-like NiAu nanoalloy (134 mV), and this is due to the plasma treatment process. In addition, plasma-treated sponge-like NiAu nanoalloy shows an excellent durable ability of HER activity for 80,000 s.