The interface property of perovskite solar cells (PSCs) is very important, which can influence the electron transmission efficiency and stability of the cells. In this text, we have discussed the stability and bonding characteristics of PbI2/TiO2 interfaces by using the first-principles method. The PbI2/TiO2 interfaces have a high interfacial binding energy of -0.93 J/m2, where the Ti-I and Pb-O bonds could form. Furthermore, the electron transport at the interfaces has been analyzed by the partial density of states by comparing the clean interfaces and interfaces with different defects. The results show that the clean PbI2/TiO2 interfaces could cause a stronger internal electric field, which might make the electron-hole pairs separate more easily at the interfaces. Also, it is found that common defects VI and Ii are relatively easy to form at the interfaces. Some defects at low concentrations might have little effect on the electron transport at the interfaces, while they are harmful only when the concentration increases. However, VPb with a high formation energy could adversely affect the electron transmission even at low concentrations. Controlling the defects at the interfaces is essential to improve the power conversion efficiencies (PCEs) and stability of PSCs.