Interfacial engineering between charge transport layers and perovskite light-emitting layers has been applied as an effective strategy to enhance performance of perovskite light-emitting diodes (PeLEDs). Herein, we introduce a Lewis base diamine molecule [2,2-(ethylenedioxy)bis(ethylammonium), EDBE] to modify the interface between the ZnMgO electron transport layer (ETL) and perovskite light-emitting layer in PeLEDs. With two amino groups in EDBE, one amine can interact with ZnMgO beneath to tune the growth of perovskite films, resulting in improved electron injection and suppressed current leakage. Meanwhile, the other amine can passivate the surface trap states of the polycrystalline perovskite films, which would eliminate trap-mediated nonradiative recombination. An enhanced performance for near-infrared PeLEDs is achieved with external quantum efficiency from 9.15 to 12.35% after incorporating the EDBE interfacial layer. This work demonstrated that the introduction of Lewis base diamine molecules as the ETL/perovskite interfacial agent is a promising way for developing high-performance PeLEDs.