||ZnO has attracted increasing attention as an electron trapnsporting layer(ETLs) of perovskite solar cells due to many advantages such as suitable energy structure, high electron mobility and solution-processability at low temperature. However, the basic nature of the ZnO can induce the proton transfer reaction at ZnO/perovskite interface, leading to poor stability. In this work, we found that utilization of self-assembled monolayers(SAMs), especially 4-methoxybenzoic acid, 3,4-dimethoxybenzoic acid and 3,4,5-trimethoxybenzoic acid on ZnO prevents the direct contact between the perovskite and ETLs, avoiding the proton transfer reaction between perovskite and ZnO. Also, strong dipole effect induced by a methoxy functional group of SAM enhances the LUMO level of ZnO, resulting in a reduction of electron transfer barrier at the ZnO/perovskite interface. As a result, the power conversion efficiency of the devices dramatically enhanced from 0.861 to 13.75% after optimizing the SAM layer.