Herein, a facile and enzyme‐free CP sensor was fabricated by in situ electrochemical reduction strategy on the surface of glassy carbon electrode (GCE). Reduced graphene oxide (RGO) was chose as supporting materials for the distribution of platinum nanoparticles (Pt NPs) to obtain improved catalytic properties. The applicability and suitability of the obtained RGO‐Pt/GCE for 4‐CP detection were also evaluated. The results indicated that the RGO‐Pt NPs modified electrode displayed much better catalysis and higher sensitivity for 4‐CP oxidation. Under optimum conditions, the oxidation peak current was proportional to 4‐CP concentration in the range from 0.1 to 500 μM with a detection limit of 51 nM. Meanwhile, it is demonstrated that the prepared sensor is also characterized by excellent feasibility, satisfactory reproducibility, good stability and high specificity. The results suggested that RGO‐Pt/GCE could be a facile, cost‐effective, and rapid tool for the prospect on‐line evaluation of 4‐CP in drinking water samples.