The　tin　coatings　are　prepared　by　immersion　plating　method　on　the　copper　substrate.　The　acid　plating　solution　is　used　in　which　thiourea　is　added　as　the　potential　adjusting　agent,　and　the　stannous　methanesulfonate　is　used　as　the　primary　salt.　The　tin　coating　is　characterized　by　a　field　emission　scanning　electron　microscopy　(FESEM)　and　the　X-ray　diffraction　(XRD).　The　macroscopical　morphology　is　researched　by　the　numeral　photos.　The　results　show　that　in　this　methanesulphonic　acid　based　plating　baths,　the　glossy　and　compact　tin　coatings　without　dendrite　tin　growth　can　be　obtained　by　immersion　plating.　The　main　phase　structure　of　the　coating　is　tin　with　body-centered　tetragonal　crystalline　structure.　The　formation　of　the　coating　can　be　divided　into　three　stages:　exquisite　instantaneous　nucleation,　planar　sandwich　growth　and　coating　closed-grained　growth.