[Objectives]  To elucidate the expression pattern and biological function of anchor protein gene (NlGPI) from the brown planthopper, Nilaparvata lugens (Stål). [Methods]  Based on transcriptome data, the full-length cDNA of the NlGPI gene was cloned with PCR and its nucleic acid and protein sequence characteristics were analyzed with bioinformatics. qRT-PCR was then used to detect the gene’s temporal and spatial expression patterns and its biological functions were determined using RNAi. [Results]  The full-length cDNA sequence of NlGPI (GenBank Accession Number: XM_022342741.2) was cloned and obtained. The ORF contained 813 nucleotides encoding 270 amino acids with a predicted molecular weight of about 27 kD and a predicted isoelectric point of 4.84. The gene has a signal peptide (Sec/SPI), the spline site of which is located between amino acids 19 and 20. This gene contains a GltG protein domain, with a total of 44 phosphorylation modification sites. A phylogenetic tree indicates that NlGPI is most closely related to the homologous gene of Laodelphax striatellus, and that anchor protein genes are highly conserved in insects. qRT-PCR indicates that the NlGPI gene displays obvious temporal and spatial specificity. The gene NlGPI was hardly expressed from the egg stage to the beginning of emergence, its expression level only increasing significantly in 1-day-old female adults. Maximum expression level was recorded in 72 h-old female adults, which was significantly higher than that in other age groups. There was no significant difference of NlGPI expression in the thorax, abdomen, ovary and intestine, but the expression level in these organs was significantly higher than in the head. The number of YLS in the interference group 24, 48 and 72 h after RNAi treatment decreased by 72.4%, 68.2% and 72.3%, respectively, relative to the control group. NlGPI knockdown significantly increased N. lugens mortality; all N. lugens in the interference group died on the 10th day after treatment, while those in the control group survived until the 16th day. Knockdown also significantly decreased the number of eggs laid and the hatching rate. In the control group, the number of eggs laid ranged from 80 to 300 and the average hatching rate was > 90%. However, in the treatment group, the maximum number of eggs laid was 56 and the average hatching rate was < 20%. [Conclusion] NlGPI is closely related to the release of YLS from the fat body to the hemolymph and plays an important role in the growth, development and reproduction of the brown planthopper. The NlGPI gene is therefore a potential target for controlling this pest.