Xanthate with low cost and strong collecting ability has great application in the recovery of sulfide mineral. Herein, a xanthate, sodium O-benzythioethyl xanthate (SBEX), with high collecting ability was prepared by introducing thioether structure, which was constructed by reactive 2-(benzylthio)-ethanol, carbon disulfide, and sodium hydroxide. The flotation performance of SBEX to chalcopyrite is yet to be explored by flotation experimental, surface tension measurements, adsorption experimental, density functional theory (DFT) calculations, and X-ray photoelectron spectroscopy (XPS) analyses. It is found that the thioether structure can increase the hydrophobicity and adsorption amount of SBEX on chalcopyrite surface, and SBEX features a higher collecting recovery toward chalcopyrite than sodium isobutyl xanthate (SIBX) and sodium phenylethyl xanthate (SPEX). The adsorption mechanism analyses reveal that two S atoms in the structure of -C(=S)-S are the reactive sites that can donate their electrons to minerals, as confirmed by DFT calculations and XPS analyses.