Abstract: The flotation property of two cationic collectors was preliminary studied for the mechanism research by zeta potential analyzer,automatic surface tensions meter.Their flotation ratio of pure quartz mineral as phosphate ore reverse collector was discussed.The different between modified cationic collector W-2 and dodecylamine among the surface tension、the contact angle、the zeta potential and the IR spectra were compared. Result showed that the water solubility,dispersion,foaming property, wettability of the W-2 were improved by the modification.The W-2 collector has better collecting performance in wider pH range.