Perovskite oxide interfaces have become a platform for the realization of many unexpected physical properties in recent years, while effective electric control of magnetism is promising for future spintronic devices. In this work, external electric field is applied to control the physical properties of LaFeO3/SrTiO3 perovskite oxide heterostructures investigated by first-principles calculations based on density functional theory (DFT). We find that external electric field can effectively modulate the band dispersion around the Fermi level of both the n-type and the p-type interfaces. Negative electric field can weaken the band shift, even leading to a two-dimensional electron gas, which is accompanied by a reversible insulator-to-metal/half-metal transition at the n-type interface. Moreover, the n-type interface perfectly realizes a transformation from G-type antiferromagnetic to ferrimagnetic at −0.3 V/Å. Meanwhile, the electric field also regulates the electronic structure of the p-type interface of the heterostructure. Our work mainly focus on using electric field to tune the interfacial electronic structure and magnetic properties of perovskite oxides heterostructures, and further pave the way to the experimental design of novel magnetoelectric interface materials.