Background/Objectives: The body color and patterns of insects play important roles in foraging, evading predators, mating, thermoregulation, and environmental adaptation. During the rearing of the QiufengN silkworm strain, a mutant with black pupal cuticle (QiufengNBP) was discovered. Preliminary map-based cloning and sequence analysis indicated that the ebony gene might significantly influence the formation of the black pupa mutant and the expression of 30K proteins. This study aims to determine the function of the ebony gene and its effect on the expression of the 30K protein during the pupal stage; Methods and Results: We employed CRISPR/Cas9 gene-editing technology to knock out the ebony gene in the Nistari strain, resulting in individuals with black pupae, named Nistari Black Pupa (NisBP). This confirmed that the ebony gene plays a crucial role in black pupa formation. Two-dimensional electrophoresis (2-DE) analysis of the pupal cuticle of NisBP and its wild-type Nistari found that the ebony gene has a significant impact on the expression of 30K proteins, which are vital for embryonic development and serve as key storage proteins; Conclusions: This study is the first to demonstrate that the ebony gene affects the expression of 30K proteins, laying the foundation for further research on their functions and providing insights into the developmental mechanisms of silkworms.