Bipolar electrochemistry is an unconventional but powerful technique in the fields of materials science and analytical chemistry. We report here the one-step cathodic deposition of NixCu1-x alloys with a composition gradient and a morphology evolution on a copper substrate, based on an in-plane potential gradient over the interface of a bipolar electrode (BPE) and an electrolytic solution. The alloy gradient was characterized using scanning and transmission electron microscopy techniques. As a result, the deposited alloy layer exhibits a composition gradient from 0 to ca. 89% Ni atoms corresponding to an abundant morphology evolution from pyramids to dendrites and to nano/microballs along the surface of the BPE. Electrochemical screenings were performed for the dissected alloy specimens as the electrocatalyst of hydrogen evolution reaction. The present work shows that bipolar electrochemistry can give access to the fabrication of alloys with abundant architectures as high throughput screening candidates.