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The diamondback moth, <i>Plutella xylostella,</i> is one of the most important pests of cruciferous crops. We have earlier shown that N⁶-(2-hydroxyethyl)-adenosine (HEA) exhibits insecticidal activity against <i>P. xylostella</i>. In the present study we investigated the possible mechanism of insecticidal action of HEA on <i>P. xylostella</i>. HEA is a derivative of adenosine, therefore, we speculated whether it acts via <i>P. xylostella</i> adenosine receptor (<i>PxAdoR</i>). We used RNAi approach to silence <i>PxAdoR</i><i> </i>gene and used antagonist of denosine receptor (AdoR) to study the insecticidal effect of HEA. We cloned the<i> </i>whole sequence of <i>PxAdoR</i> gene. A BLAST search using NCBI protein database showed a 61% identity with the <i>Drosophila</i> adenosine receptor (DmAdoR) and a 32-35% identity with human AdoR. Though the amino acids sequence of <i>PxAdoR </i>was different compared to other adenosine receptors, most of the amino acids that are known to be important for adenosine receptor ligand binding and signaling were present, But only 30% binding sites key residues was similar between PxAdoR and A1R. HEA, at a dose of 1 mg/mL, was found to be lethal to the second-instar larvae of<i> P</i>. <i>xylostella</i>, and a significant reduction of mortality and growth inhibition ratio were obtained when HEA was administered to the larvae along with <i>PxAdoR</i>-dsRNA<i> </i>or antagonist of AdoR (SCH58261) for 36, 48, or 60 h. Especially at 48 h, the rate of growth inhibition of the <i>PxAdoR </i>knockdown group was 3.5-fold less than that of the HEA group, and the corrected mortality of SCH58261 group was reduced almost 2-fold compared with the HEA group. Our findings show that HEA may exert its insecticidal activity against <i>P. xylo</i><i>s</i><i>tella</i> larvae via acting on PxAdoR.