In recent years, researchers have developed spray deposition technology to fabricate tin oxide (SnO2) electron transport layer (ETL) with the aim of manufacturing high-efficiency, large-area perovskite solar cell (PSC). However, the power conversion efficiency (PCE) of PSC based on sprayed SnO2 ETL remains inferior to that of the spin-coated SnO2 ETL. Herein, we demonstrate the combined use of spray deposition and genetically-engineered M13 bacteriophages to fabricate M13-SnO2 biohybrid ETL for PSC application. The spray-deposited M13-SnO2 ETLs exhibited mesoporous morphologies with >85% transmittance in UV-vis region. Though the use of M13-SnO2 ETL, the sequential-deposited PSCs achieved a maximum PCE of ~22.1%. The improved performance of the PSC is attributable to the mesoporous morphology of M13-SnO2 ETL that facilitated the phase conversion of PbI2 into perovskite. When sprayed on large–area (~62 cm2) substrates, the M13-SnO2 based PSCs displayed a highly consistent PCE, demonstrating the excellent scalability of spraying process. Furthermore, M13-SnO2-based PSCs exhibited higher ambient stability compared to the SnO2-based PSCs.