In this paper,ZnO modified pencil graphite electrode(ZnO/PGE) was prepared by dropping ZnO nanoparticles on the surface of pencil graphite electrode(PGE)The ZnO/PGE showed an unexpectedly electrogenerated chemiluminescent behavior in NaOH solution with potassium persulfate(K2S2O8) as a coreactant.The possible mechanism of electrogenerated chemilumnescence(ECL) was investigated.Based on the principle that ECL of ZnO/PGE was quenched in the presence of phenol,an ECL sensor was developed for the detection of phenol.The ECL intensity was linearly changed with the logarithm of phenol concentration in the range of 2×10-8-2×10-6 mol/L,and the detection limit(S/N=3) was 1×10-8 mol/L.With the advantages of broad linear range,good reproducibility and storage stability,the proposed method was applied in the analysis of phenol in industrial waste water,with recoveries of 96.5%-104.5%.