Conjugated polymers have been explored as promising hole-transporting layer (HTL) in lead sulfide (PbS) quantum dot (QD) solar cells. The fine regulation of the inorganic/organic interface is pivotal to realize high device performance. In this work, we propose using CsPbI₃ QDs as the interfacial layer between PbS QD active layer and organic polymer HTL. The relative soft perovskite can mediate the interface and form favorable energy level alignment, improving charge extraction and reducing interfacial charge recombination. As a result, the photovoltaic performance can be efficiently improved from 10.50% to 12.32%. This work may provide new guidelines to the device structural design of QD optoelectronics by integrating different solution-processed semiconductors.