In this study, we constructed a functional nanoparticle system with elastin-like polypeptide (ELP) depending on the self-assembly property of coat protein (CP) from cowpea chlorotic mottle virus (Cowpea chlorotic mottle virus, CCMV). The two fusion proteins of native ELP-CCMV (ELP-CCMV CP, NCP) and ELP-CCMV with mutant amino acids were separately successfully expressed in E. coli BL21 after structural functionalization through cloning an ELP at the N-terminus of CP. Compared with the yield of NCP (74 mg/L), that of VCP was increased by 83.78%, and thus suggesting that the expression of VCP was better than that of NCP. The above fusion proteins could form the stable virus-like particles (VLPs) through self-assembly and effectively encapsulate Pt nanoparticles in response to multiple conditions of pH value, low concentration of salts and temperature. Meanwhile, VCP completed self-assembly under mild conditions (neutral pH, low concentration of salts and room temperature). The apparent rate constant of Pt@VCP nano-catalyst (0.17 min-1) was 2.8 times than that of the citric acid modified Pt-CA nanocatalyst in 4-nitrophenol reduction reaction catalyzed by VLPs, and thus indicated Pt@VCP was of excellent catalytic activity. Pt@VCP with the apparent activation energy 22.0 kJ/mol was also of lower energy barrier when compared with that of Pt@VCP (14.1 kJ/mol). The superior catalytic activity of Pt@VCP was attributable to confinement effect of the protein nanocage Pt@VCP and synergistic effect of the substrate 4-nitrophenol, Pt nanoparticles and surface functional group of the VLPs.