A cauliflower-like nanostructured Pd film (CNPF) has been fabricated by just applying one double-potential step on a pure Pd substrate in a KCl solution. The CNPF formation mainly involves the formation of K2PdCl4 salt from pure Pd and its electroreduction to Pd atoms. The as-prepared CNPF electrode exhibits high electrocatalytic activities toward the oxidation of ethanol and ascorbic acid (AA). The CNPF electrode is also employed to detect AA by means of constant potential amperometry (CPA) and cyclic voltammetry (CV), and good analytical performances in the higher-concentration regions are obtained. In CPA studies performed at -0.4 V, the oxidation current is linearly dependent on AA concentration in the range of 0.1-7.5 mM with a detection limit of 80 mu M (based on S/N = 3), a short response time of about 3 s and a high sensitivity of 589.80 mu A mM(-1) cm(-2). Meanwhile, the peak current responses in CVs are linear over the broad range of 0.1-35 mM with a sensitivity of 178.56 mu A mM(-1) cm(-2). Besides, the CNPF electrode can also be used to detect AA in medicine vitamin C tablet with satisfactory results. (C) 2013 Elsevier Ltd. All rights reserved.