<p>Insects play a crucial role in maintaining the functionality and stability of grassland ecosystems. Limitations in traditional morphological methods and the shortage of knowledgeable taxonomists have been mitigated by DNA barcoding tools. DNA metabarcoding is rapidly emerging as a cost-effective approach for large-scale biodiversity assessments and pest monitoring. In this study, we used DNA metabarcoding to conduct an in-depth analysis of insect biodiversity in four different types of grasslands in Inner Mongolia. During the nearly 3-month investigation period, 132 bulk samples were assigned 1048 Barcode Index Numbers. Insect biodiversity in sandy grasslands was significantly lower than that in typical grasslands and the agropastoral ecotone. In addition, the identification of inconsistencies at the genus (6.2%) and species (31.3%) levels could be improved. This result highlights the need to enhance and expand DNA barcode reference libraries. Among the 14 arthropod orders identified, the insect order Diptera was the most abundant in all the grassland types. These results indicate that DNA metabarcoding represents a valuable tool for improving taxonomic understanding and biodiversity assessment quality in grassland insect biodiversity monitoring. Moreover, this approach provides support for more comprehensively understanding insect diversity in different types of grasslands.</p>