Grylloblattids are an ancient insect lineage crucial for understanding insect evolution and phylogeny. Systematic and in-depth studies of this taxon are still needed. This investigation advances grylloblattid systematics through three principal contributions: taxonomic revision of extant Grylloblattidae with redesigned diagnostic keys; description of a new species Grylloblattella aletaiensis sp. nov.; and geometric morphometrics analyses to quantify interspecific differentiation in the first tergum morphology across all genera of extant Grylloblattidae. We further sequenced and assembled the first complete mitochondrial genome (16 625 bp) from an Asian-lineage grylloblattid, revealing conserved gene arrangement and structural conservation shared with polyneopteran lineages. Phylogenetic delineation of basal lineages within Grylloblattidae was conducted using concatenated mitochondrial and nuclear loci, coupled with divergence time estimation analyses to reconstruct historical biogeographic dynamics. This multidisciplinary operational framework synthesizes molecular phylogenetics and temporal biogeography, establishing a robust empirical foundation for interdisciplinary research in paleoentomology, evolutionary developmental biology, and evidence-based conservation prioritization for relict insect lineages. The evolutionary history of grylloblattids is closely coupled with global geo-climate changes since the Mesozoic Era, serving as a model system for investigating the macroevolution of insects.