Copper nanoparticles (CuNPs) have attracted great interest in various biomedical research fields due to their superior optical and plasmonic properties. In the present study, we synthesized bovine serum albumin (BSA)-coated CuNPs (BSA-CuNPs) by adopting the aqueous reduction method in 2-step procedures. The prepared BSA-CuNPs were characterized in vitro for their physical characteristics and photothermal activity. The successful synthesis of BSA-CuNPs was verified through transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and ultraviolet-visible (UV-VIS) light spectroscopy. The prepared BSA-CuNPs revealed a great light-to-heat conversion capacity and good photothermal stability. Notably, accompanied by laser irradiation, the BSA-CuNPs elicited significantly higher cytotoxicity on tumor cells than the control group. Preliminary animal studies to determine the biosafety and pharmacokinetics (PK) profiles exhibited that the BSA-CuNPs have a maximum tolerable dose (MTD) of 16 mgCu/kg and a relatively long plasma half-life of 1.98 h. Overall, our findings demonstrated that BSA-CuNPs might be a potential photothermal therapeutic agent for cancer treatment.