This paper sorts out biotechnology projects in DARPA’s fiscal year 2021 budget document, and analyzes its ideas for promoting the biotechnology development from the budget project layout perspective. According to the layout of projects, the biotechnology projects of DARPA mainly cover the research areas of biosecurity, brain and neuroscience, recovery and enhancement of body function, treatment of war wound, and so on. The specific ideas of DARPA promoting the development of biotechnology include: focusing on infectious disease detection and protection to improve biosecurity capability; promoting neural interface and neuro drug research to overcome neurological dysfunction; strengthening individual physiological and psychological intervention research to improve soldiers' body function recovery and enhancement ability; using the methods of cross-science and analytical biology to explore the treatment of war wound. Based on these, this paper concludes that DARPA is focusing on strengthening the advantages of interdisciplinary integration to further explore and utilize the great potential of biological systems, and help maintain the world-leading advantage of US military technology generation difference.