Small compounds are often utilized to adjust the cathode interface of organic solar cells (OSCs) due to their low batch change, easy synthesis, unambiguous chemical structure, and low cost. In this work, the alcohol-soluble small molecule material Glycolic acid was doped into the electron transport material Poly(9, 9-bis(3′-(N, N-dimethyl)-N-ethylammoniumpropyl-2, 7-fluorene)-alt-2, 7-(9, 9-dioctylfluorene)) dibromide (PFN-Br) to modify the performance of the cathode interface layer (CIL). The CIL doped with Glycolic acid has better surface morphology, which is conducive to charge transport and extraction. In addition, the introduction of Glycolic acid improves the hydrophilicity of CIL, makes the metal electrode have good contact with CIL, and helps to improve the stability of the OSCs. Additionally, it suppresses the device's trap-assisted recombination and bimolecular recombination, hastening exciton dissociation and charge collection. As a result, the power conversion efficiency (PCE) of OSCs based on PM6: Y6 blend film has risen from 15.26% to 15.91%. After 312hours of stability testing, the aforementioned doped devices still have device performance higher than standard device. Furthermore, based on PBDB-T: IT-M mix film, the PCE of the doped device and reference device was 11.29% and 10.55%, respectively. This study suggests that using the alcohol-soluble small-molecule material Glycolic acid can increase the organic solar cells' (OSCs') efficiency. This study provides a new method for manufacturing high-performance OSCs.