Abstract: The CdTe quantum dots (QD′s) was prepared with mercaptoethanol as stabilizing agent,and fluorescence quenching effect of CdTe QD′s was observed when mixed with solution containing Cu(Ⅱ) ion.The magnitude of decrease in fluorescence intensity was found to keep direct proportionality with the concentration of Cu(Ⅱ) ion present.Based on this fact,a fluorospectrophotometric method for determination of Cu(Ⅱ) ion utilizing the fluorescence quenching effect of CdTe QD′s was proposed.By taking concentration of CdTe QD′s at 1.25×10-4mol·L-1,linearity range of Cu(Ⅱ) found was between 32.0-320.0 μg·L-1 with detection limit (3s/k) of 1.06 μg·L-1.The proposed method was used in the determination of Cu(Ⅱ) in plant samples,giving values of recovery in the range of 99.5%-100.2%.