The stripping current arising from the oxidation of Cd was related to the concentration of Cd²⁺ in the sample. This study presents the determination of Cd(II) at low concentration μg/L levels by square wave anodic stripping voltammetry (SWASV) on an activated bismuth-film electrode (BFE). The electrode was initially modified by an electrochemical method, and then the electrodeposited bismuth-film was prepared again to improve the electrode, thereby enhancing the sensitivity to trace amounts of target Cd²⁺. The surface of glassy carbon electrode (GCE) before and after modification was characterizad by SEM, CV, EIS, and SWV. The parameters for the determination of the Cd²⁺ were investigated with the view of its application toward real samples containing low concentrations of Cd²⁺. Using the selected conditions, the limit of detection is 1 μg/L for Cd²⁺ at a preconcentration time of 10 min.