Abstract  [Aim]  E74 is a key transcription factor induced by 20E in insects that plays an important regulatory role in insect metamorphosis and development. However, few studies have been conducted on the role of E74 in mites. This study aims to investigate the function of the transcription factor E74 from Panonychus citri deutonymph to adult and provide potential targets for mite control. [Methods]  RT-qPCR was used to analyze the expression characteristics of E74 during the different developmental stages of P. citri from deutonymph to adult. Three different treatments (dsRNA, siRNA, dsRNA+siRNA) were used to interfere with PcE74 through the leaf-mimicking method using RNAi technology. The silencing efficiency was analyzed to determine the optimal interference mode, and the role of PcE74 was explored during the deutonymph-adult transition. [Results]  PcE74 was expressed during all developmental stages from deutonymph to adult. The expression of PcE74 increased between the 2-hour deutonymph stage to the 16-hour deutonymph stage, before declining during the third instar adult stage where the expression level remained low. The RNAi experiment showed that the interference efficiency of dsPcE74+siPcE74 (54%) was significantly higher than dsPcE74 (14%) and siPcE74 (24%), and the molting percentage was significantly lower than the control (P < 0.05). An abnormal phenotype identified was characterized by the inability of the stationary phase of the deutonymph to produce old epidermis, which resulted in death. siRNA can enhance RNAi efficiency at the phenotypic level, and the RNAi efficiency of dsRNA+siRNA is superior to dsRNA or siRNA. [Conclusion]  PcE74 is involved in the regulation of the developmental process from deutonymph to adult in P. citri. Further investigation is needed on genes that interact with E74 in the molecular regulatory pathway.