The effects of sodium hydroxide and sodium carbonate on the flotation of spodumene were investigated by flotation tests, XPS and SEM measurments and thermodynamic analysis. A collector YOA (a mixture of 90% oleic acid and 10% dodecyl amine) was used in the flotation. It was found that sodium hydroxide showed an activation effect whereas sodium carbonate showed a depression effect on the flotation of spodumene. This difference in flotation performance was consistent with the measured contact angles of spodumene treated in sodium hydroxide and sodium carbonate solutions, respectively. XPS results indicated that the pretreatment of spodumene surface by sodium hydroxide gave larger relative contents of Al and Li on spodumene surface than that of sodium carbonate, and the scanning electron microscopy images showed rougher surfaces indicating leaching of the mineral surface. The spontaneity of possible reactions associated with the surface dissolution of spodumene in alkaline solutions was also examined, and the results could largely account for the observed difference in surface dissolution of spodumene in sodium hydroxide and sodium carbonate solutions.