Phototherapy, a tumor therapeutic modality, has been widely studied due to its advantages of minimal invasiveness, low side effect, and high therapeutic efficacy. However, single phototherapy cannot achieve complete tumor elimination. Recently, the emerging two-dimensional nanomaterials have attracted great attention in the field of phototherapy. Here, FePS₃ nanosheets were prepared, and then its phototherapeutic properties were investigated. The bulk FePS₃ was synthesized by a high-temperature solid-phase method and FePS₃ nanosheets were obtained by an ultrasonic-assisted liquid phase exfoliating method. The nanosheets displayed particle morphology with average hydrated size of less than 200 nm (153 nm in average), performed photothermal conversion efficiency of 19.7% under 1064 nm laser irradiation, and generated reactive oxygen species under 660 nm laser irradiation. Cell experiment results showed that FePS₃ nanosheets had excellent photothermal and photodynamic therapeutic effects. Therefore, FePS₃ nanosheets can be used as both photothermal agent and photosensitizer to achieve combined photothermal-photodynamic therapy for treating tumors, which shows great application potential.