Evolutionary developmental biology (Evo-Devo) investigates the genetic and developmental mechanisms underlying morphological diversity across species. Arthropods and nematodes, as two prominent invertebrate phyla, offer rich comparative opportunities to explore the relationship between gene regulatory networks (GRNs) and morphological evolution. This paper presents a comprehensive analysis of GRNs and morphological evolution in arthropods and nematodes, aiming to elucidate conserved patterns and species-specific innovations.Through comparative studies of GRNs, we identify both conserved regulatory elements governing core developmental processes and divergent regulatory architectures associated with morphological diversity. By integrating genetic data with morphological observations, we explore the evolutionary changes in body plans, appendage morphology, and other key traits. Case studies highlight the evolution of segmentation, appendage development, and nervous system complexity, revealing instances of convergent and divergent evolution. Our analysis underscores the intricate interplay between genetic changes and morphological outcomes, shedding light on the underlying mechanisms driving evolutionary innovations. Furthermore, we discuss the implications of our findings for understanding the evolutionary trajectories of arthropods and nematodes, as well as broader implications for Evo-Devo research