A　biodegradable　Ca-P　coating　mainly　consisting　of　β-tricalcium　phosphate　(β-TCP)　was　fabricated　on　pure　magnesium　via　the　chemical　deposition　in　a　simulated　Hank＇s　solution.　The　method　significantly　accelerated　the　coating　formation　on　magnesium.　Moreover,　the　morphology,　phase/chemical　composition,　the　coating　formation　mechanism　as　well　as　degradation　behavior　in　phosphate　buffered　saline　(PBS)　solution　were　investigated.　Scanning　electron　microscopy　(SEM)　images　showed　that　the　coating　had　three　layers　and　X-ray　diffraction　(XRD)　patterns　showed　that　the　coating　mainly　contained　Ca3(PO4)2　and　(Ca,　Mg)3(PO4)2.　Electrochemical　test　showed　that　the　corrosion　current　density　(Icorr)　of　the　coated　Mg　was　decreased　by　about　one　order　of　magnitude　as　compared　to　that　of　pure　magnesium.　The　immersion　test　indicated　that　the　coating　could　obviously　reduce　the　degradation　rate.　©　2012　The　Chinese　Society　for　Metals.