Abstract Perovskite solar cells (PSCs) have attracted more attentions in recent decade, and the power conversion efficiency (PCE) has reached 24.2%. While some issues such as cost and stability must be solved for commercialization. One of the most effective ways is to develop inorganic hole-transporting materials (HTMs) for PSCs. In the present work, CuInS2 quantum dots (CIS QDs) were synthesized using a modified hot-injection method and applied to PSCs as an HTM. A high value of PCE (18.8%) for the optimized solar cells with CuInS2 as an HTM was achieved, which was very close to the PCE of a device with Spiro-OMeTAD as an HTM (19.2%). Moreover, the stability of CuInS2-based solar cells was greatly improved compared to those made with Spiro-OMeTAD. The PCE of CuInS2-based solar cells only decayed by 9% of the original value after 30 days, while that of the solar cells based on Spiro-OMeTAD decayed dramatically by 33% of the original value within 15 days. These results in this study demonstrate that CuInS2 is a promising inorganic hole-transporting material for the fabrication of PSCs with high PCE and improved stability.