Based on the experimental strategies including fractional factorial design (FFD), path of the steepest decent (PSD), and central composite design (CCD) coupled with response surface methodology, the composition of lead-free Sn-Bi deposits plated under dc mode can be precisely controlled and predicted. As a result, deposits of the eutectic point, 42Sn-58Bi, as well as tin-rich deposits (80Sn-20Bi and 90Sn-10Bi in wt %) for lead-free solders can be obtained, although the Sn-Bi chloride-based solutions were recognized as a complicated electroplating system. In the FFD study, pH, current density, and citric acid concentration were identified to be the key factors affecting the composition of Sn-Bi deposits. The effects of current density and citric acid concentration on the composition of Sn-Bi deposits were examined in the PSD and CCD studies to construct a reliable model for composition control. A robust electroplating setting derived from this model is applicable to other solutions with variable compositions. A linear relationship between Sn/(Sn+Bi) in the deposit and [Sn4+]/[Sn4++Bi3+] in the electroplating bath is obtained under the robust setting. From the morphologies and crystalline information, all binary Sn-Bi deposits prepared in this work belong to heterogeneous alloys.