Divalent/trivalent　cobalt　hydrotalcite-like　compounds　(Co2+-Co3+　HTlc)　were　synthesized　via　precipitation　under　mild　alkaline　conditions　by　using　NaOH　as　precipitant　and　methanol-water　as　solvent.　The　influences　of　synthetic　parameters　including　CH3OH:H2O　volume　ratio,　precipitation　pH,　and　hydrothermal　treatment　on　the　HTlc　formation　were　investigated.　The　crystalline　phase,　morphology,　and　chemical　composition　of　the　syn-thesized　samples　were　characterized　by　XRD,　FTIR,　SEM,　TG-MS,　and　iodometric　titration.　The　formation　of　Co2+-Co3+　HTlc　was　strongly　affected　by　the　methanol　content　and　a　single　Co2+-Co3+　HTlc　phase　was　obtained　by　raising　the　CH3OH:H2O　ratio　to　4:1-8:1.　It　was　suggested　that　the　presence　of　methanol　increased　the　con-centration　of　dissolved　oxygen　and　promoted　the　oxidation　of　Co2+　into　Co3+,　leading　to　complete　trans-formation　of　alpha-Co(OH)2　into　Co2+-Co3+　HTlc.　Moreover,　single-phased　Co2+-Co3+　HTlc　was　available　at　pH　between　10　and　12,　and　they　were　hydrothermally　stable　by　treatment　at　60　degrees　C　for　24　h.　Under　the　synthetic　conditions,　complete　precipitation　of　cobalt　ions　was　achieved.　This　highlights　that　the　developed　synthesis　process　is　an　efficiency　way　for　quantitative　synthesis　of　cobalt　HTlc.