The impact of an asteroid on the Earth may lead to catastrophic consequences, so it is necessary to explore effective approaches for protection. This paper aims to analyze the defense strategies against an asteroid impact on the Earth, focusing on three methods: impact of aircraft, nuclear explosion, and gravitational traction. This paper first outlines the basic characteristics of asteroids and their potential risk of impacting the Earth. Subsequently, it analyzes the status quo, advantages and disadvantages, and applicable conditions of the three defense methods. It is found that aircraft impact is mature but time-consuming. Nuclear explosions are fast and effective but carry political and radiation risks. Gravitational traction is safe and stable but takes a long time. Different approaches apply to different types of asteroids and warning times, and these factors need to be considered comprehensively when choosing. This paper then discusses the exploring directions for improvement of the various methods and points out possible future trends, including technology convergence and multinational cooperation. Finally, the importance of choosing the appropriate methods of defense based on the size of the asteroid and the warning time is emphasized.
