Since 2014, there have been increasing numbers of undernourished people in the world, mainly distributed in developing countries. At the same time, the rapid growth of China's agricultural FDI (Foreign Direct Investment) has attracted international attention. There are different opinions on whether China's fast-growing agricultural investment can contribute to promoting global food security. The objective of the article is to clarify the consensus and differences of current research, and explore the actual impacts of China's agricultural FDI. This paper adopts the Grounded Theory to sort out the characteristics, reasons, and impacts of China's agricultural FDI and their intrinsic relationship. The results show that private enterprises are the mainstay of China's agricultural FDI, mainly concentrated in developing countries in Asia and a few developed countries such as Singapore, New Zealand, and the United States. As the investment model is transformed from land leasing to mergers and acquisitions, China's agricultural investment links are transformed from planting to full-industry chain operations. The motives of Chinese agricultural FDI are affected by corporate goals, national strategies, and the international environment. For China, overseas agricultural investment guarantees national food security, helps expand the agricultural product market, and enhances China's influence. For the host country, China's agricultural investment brings about agricultural technology, management experience, and employment opportunities. However, in the actual investment process, the investment model of land leasing has caused the instability of local farmers' livelihoods, and the excessive pursuit of profits by Chinese companies has also led to an unfair distribution of agricultural products. All of these may bring some challenges to the social and economic development of the host country to a certain extent, affecting the realization of win-win goals. In order to achieve a win-win goal, at the enterprise level, Chinese companies should make the investment model fit the interests and development goals of the host country, rationally choose the investment location, and abide by local rules. At the government level, the Chinese government should guide enterprises to focus on the less developed countries and regions that are most in need of introducing agricultural investment, and provide enterprises with risk protection. At the international level, it is necessary to strengthen the formulation and improvement of international agricultural investment rules, guide the public to form an objective understanding of agricultural investment behavior and impact, and create a suitable environment for international agricultural investment.