Objective: This study aimed to investigate the effect of Euglena gracilis on the quality and antioxidant activity of Chiffon cake and provide a reference for the application of E. gracilis in baked goods. Methods: E. gracilis powder (0.0%, 2.0%, 4.0%, 6.0% and 8.0%) with different contents were applied to Chiffon cake. The specific volume, water content, color, texture characteristics, sensory quality score, and antioxidant capacity of the cake were studied. Results: The addition of E. gracilis powder reduced the specific volume and the brightness of the cake, but had little effect on the water content. As the content of E. gracilis powder increased, the hardness, adhesiveness and chewability of the cake increased observably, while the elasticity, resilience and cohesion did not change a lot. The addition of E. gracilis powder significantly increased the antioxidant capacity of the cake, and statistical analysis showed that the antioxidant capacity was positively related to the content of E. gracilis powder (P<0.01). According to texture and sensory analysis, the sensory quality score of the cake with 4.0% E. gracilis powder was the highest. Conclusion: The application of E. gracilis powder into Chiffon cake significantly improved the antioxidant capacity, nutritional value of the cake and the quality of the cake as well.