The work aims to develop a silane coupling agent which can be used for metal surface protection treatment independently. A trifunctional silane coupling agent (TSC, yield 95%) was synthesized based on thiol-ene click chemistry reaction of mercapto-trimethoxysilane (MPS) and trivinyltrimethylcyclotrisiloxane (TEMS). A dense layer of corrosive coupling agent pro-tective coating was obtained on the surface of tinplate. Chemical structure of the synthetic product was characterized with FTIR and 1H NMR. Coating structure was analyzed with XPS, and morphology was characterized with SEM. Properties of the coating cured with TSC hydrolyzate were characterized based upon thermogravimetric analysis, polarization curve, salt spray corrosion test, etc. Infrared results showed that double-bond stretching vibration absorption peaks (νC=C), (νC—H) and (νS—H) of the raw materials disappeared after the reaction, indicating that the reaction occurred. The 1H NMR analysis showed that the product structure was target product TSC. XPS test results showed that Si—O—Fe covalent bond formed on the coating and metallic surface. Thermal stability of the TSC coating was better than that of MPS hydrolysate coating. Salt spray accelerated corrosion test indicated that protective properties of TSC was obviously superior to that of MPS, and corrosion rate was 2.60×10?2 mm/a. Hardness of the TSC coating was up to 5H. SEM analysis showed that the TSC coating surface was smoother and less defective than MPS coating. A multi-silicon coupling agent is synthesized and can be directly used for surface treatment and protection of tinplate after hydrolysis. The protective coating exhibits excellent performance.