Antimony trisulfide (Sb ₂ S ₃ ) is one of the ideal absorbers for environmentally viable solar cells (SCs). However, interfacial carrier recombination and unsatisfactory interfacial band alignment restrict the performance of Sb ₂ S ₃ SC. To address the aforementioned issues, copper antimony sulfide (CuSbS ₂ ) is introduced as a hole transport layer (HTL) into the FTO/CdS/Sb ₂ S ₃ /Au structure. The short-circuit current density (J _SC ), open-circuit voltage (V _OC ), fill factor (FF), and power conversion efficiency (PCE) of typical Sb ₂ S ₃ SC are 23.68 mA cm ⁻² , 1.09 V, 60.98%, and 15.68%, respectively. The performance of typical Sb ₂ S ₃ SC is significantly improved by introducing HTL to construct the initial device. By further adjusting the physical parameters of HTL and absorber, including thickness, doping concentrations, bulk defect densities, and interface defect densities (N _it ), the J _SC , V _OC , FF, and PCE of optimized Sb ₂ S ₃ SC reached 21.06 mA cm ⁻² , 1.33 V, 86.32%, and 24.21%, respectively. Introducing CuSbS ₂ as HTL effectively enhances the N _it tolerance of device. Even when the N _it of Sb ₂ S ₃ /CuSbS ₂ reaches 10 ¹⁸ cm ⁻² , the Sb ₂ S ₃ SC still exhibit a PCE of over 22% with the N _it of the CdS/Sb ₂ S ₃ reaching 10 ¹² cm ⁻² . This device also exhibits a PCE of over 22% at 400 K. This result paves the way for the design of highly stable and environmentally viable Sb ₂ S ₃ SCs.