The development of multifunctional electrocatalytic materials for energy storage, conversion and electrochemical sensing with the characteristics of low cost, high catalytic activity, and high stability has far-reaching significance. In recent years, Schiff base complexes have become the preferred materials for electrochemical research interests because of their special structure and the multiple active sites on the surface. However, there are few studies on Schiff base catalysts for the multifunctional application, especially in electrochemical detection. In this paper, cobalt Schiff base complex was synthesized by solution precipitation method and then was phosphorized to obtain the multifunctional catalyst denoted as CoPO–CN. The electrocatalytic activity was measured in the presence and absence of urea alkaline solution, and the results showed that the onset potential for urea oxidation reaction (UOR) and oxygen evolution reaction (OER) were 1.35 and 1.52 V versus reversible hydrogen electrode (vs. RHE), respectively. The electrochemical sensing performance for ascorbic acid (AA) indicated that the detection sensitivity was 217.2 μA mM–1 cm–2, and the detection limit was 3.84 μM. Our work creatively used the phosphorized cobalt Schiff base for multifunctional application, not only providing new insights for the multifunctional application of Schiff base catalyst in energy conversion, but also pointing a new method for detecting small biomolecules, especially ascorbic acid. [ABSTRACT FROM AUTHOR]