A novel nanosensor based on CdSe quantum dots (QDs) capped with 8-hydroxyqunoline (HQ) was developed for Al3+ ions determination in aqueous solutions. The method is based on the fluorescence enhancement of the HQ functionalized QDs in the presence of Al3+ ions, due to the strong interaction between Al3+ and HQ. Prepared nanosensor exhibited an acceptable selectivity and sensitivity for Al3+ ions in the presence of other metal ions. Plot of Log(I/I0) against Log[Al3+] shows a good linearity in the range of 0.02–3.0 mM, and the method could be used for detection of Al3+ ions concentration in aqueous solutions.