Highly biocompatibIe near-infrared-emitting CdSeTe alloyed quantum dots (QDs) were fabricated in aqueous medium with octa-aminopropyl poIyhedral oligomeric sllsesquioxane (OA-POSS) as the capping agent. By changing the size and composition of CdSeTe alloyed QDs the fluorescence emission peak reached the near infrared (NIR) region (681 nm) with a photoluminescent quantum yield (QY) of 26.4%. POSS CdSeTe QDs were prepared by conjugating OA-POSS to CdSeTe QDs through condensation reaction utllizing [DC. And the optical properties of CdSeTe QDs were retained with improved biocompatibllity. Furthermore, the as-prepared NIR-emitting POSS CdSeTe alloyed QDs have been successfully applied to SiHa cell imaging, which demonstrates their promising applications in the biomedical field.