We investigated the accumulation of energy substances, dynamics of flight muscle development, changes in energy substances accumulation, and flight muscle structure after flight activities in female adults of the green lacewing Chrysoperla sinica (Tjeder), a common natural enemy of various insect pests in China. Virgin individuals were chosen at 24, 72, and 120 h after eclosion for energy substance determination and flight muscle observation in this study. Individuals with strong flight ability at 72 h after eclosion were selected for tethered flight assays, followed by detection of energy substances, and flight muscle observation. The results showed that virgin female adults had the highest fat content 72 h after eclosion. Sarcomere length and myofibril diameter changed significantly with age, with the lowest at 24 h after eclosion. With an increase in flight distance, the fat and glycogen contents, sarcomere length, and volume fraction of the transverse tubular system (T-system) decreased and myofibril diameters increased. The volume fraction of the mitochondria did not significantly change, but the structure of the mitochondrial membrane was destroyed, inclusions were reduced, and cavities appeared. The reserves of energy substances, especially lipids, are closely related to the flight ability of C. sinica. The observational results of both flight muscle structure and morphology of mitochondria build a strong relationship with flight behavior. This research should help reveal the regulatory mechanism of flight activity of C. sinica.