In order to improve the performance of Sn-58Bi lead-free solder, the Sn-58Bi-0.1Ti nanometer reinforced composite solder was prepared by incorporating 0.1% Ti nanoparticles into the Sn-58Bi solder. In this paper, the effect of adding Ti nanoparticles on the growth behavior of intermetallic compounds (IMC) in Sn-58Bi/Cu solder joints during thermal cycling was studied. The results showed that a scallop-like Cu₆Sn₅ IMC layer was formed at Sn-58Bi /Cu and Sn-58Bi-0.1Ti/Cu interface after reflow soldering. After 300 thermal cycles, a layer of Cu₃Sn IMC was formed at the Cu₆Sn₅/Cu interface. The thickness of IMC layer of Sn-58Bi/Cu solder joint and Sn-58Bi-0.1Ti/Cu solder joint is proportional to the square of thermal cycling time. However, the IMC thickness of Sn-58Bi-0.1Ti/Cu solder joint is significantly lower than that of Sn-58B/Cu solder joint, which indicated that the addition of Ti nanoparticles can effectively inhibit the excessive growth of interfacial IMC during the thermal cycle process. In addition, the IMC layer diffusion coefficients of these two solder joints were calculated, and it was found that the diffusion coefficients of IMC layer in Sn-58Bi-0.1Ti/Cu solder joint (overall IMC, Cu₆Sn₅ and Cu₃Sn IMC) were smaller than that of Sn-58Bi/Cu solder joint, which explained the inhibitory effect of Ti nanoparticles on the interface IMC layer to some extent.