In this Article, high-quality gold nanocrystals (Au NCs) with various shapes including concave cubic, trisoctahedral, cubic, rod-like, and quasi-spherical have been successfully produced in high yield via adding a trace amount of NaBH, solution into growth solutions mainly composed of HAuCl4, ascorbic acid, and surfactants. The sizes and shapes of as-prepared Au NCs can be tuned by the compositions of the growth solutions and the amount of NaBH4 added. The electrocatalytic performance of differently shaped Au NCs for methanol oxidation was studied; as-prepared trisoctahedral or concave cubic Au NCs are more highly active electrocatalysts for methanol oxidation due to the presence of high-index facets on their surface.