Abstract: Silver nanoparticles (AgNPs) exhibited better chemiluminescence (CL) catalysis activity in luminol-K3Fe(CN)6 system under alkaline condition. It was found that the CL intensity of luminol-K3Fe(CN)6-AgNPs was strongly inhibited in the presence of hydroquinone (HQ). Based on the luminol-K3Fe(CN)6-AgNPs CL system, a sensitive method to detect HQ by flow injection(FI) coupled with chemiluminescence (CL) detection was described. Under the optimized conditions, the sensitive detection of HQ could be realized and the detection limit of HQ was calculated to be 3.0 × 10-11 mol/L with a linear range of 1.0 × 10-10~1.0 × 10-7 mol/L. The relative standard deviation of 1.4% for 11 replicate determinations of 5.0 × 10-9 mol/L was obtained. The method was applied to the HQ analysis of river water and tap water samples with recoveries of 98.0 %~100.8% and 99.1%~100.4%, respectively. The possible mechanism of AgNPs enhancing effect on the weak CL emission of K3Fe(CN)6 system and the inhibition effect of HQ on the system was discussed by fluorescence spectrophotometer