Abstract: To further enhance the adsorption properties of activated carbon (AC), platinum was planted on the surface of AC to enhance its catalytic properties. The obtained composite was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM). After that, two filters were made respectively with unmodified AC and Pt nanoparticles modified AC (PtNPs/AC) as filtration layer, and planted in air purification machine. To further evaluate the adsorption properties of PtNPs/AC, the purification machine was placed in 30 m ³ standard environmental test chamber to study its adsorption ability to TVOC from secondhand smoke. The results showed that the removal efficiency of TVOC was 72.05% by using the filter with unmodified AC, while that of TVOC was 95.63% by using the filter with PtNPs/AC. It was thus indicated that the adsorption properties of AC can be remarkably increased by modification with Pt.