The space Internet constellation system is an important component of China’s space information infrastructure and has become a focus of international competition in future. However, China is still in the preparatory stage of the space Internet constellation system construction. We started late and are faced with many risks such as a backward space resource position, lack of independent standards, a weak foundation for technological development, limitation in traditional application fields, and uncontrollability of network security; therefore, China’s space Internet constellation system is still far from supporting rapid economic and social development. Facing the opportunities and challenges, we overview the space Internet constellation system development in China and analyze the macro demand for space Internet construction. Subsequently, we analyze the development trend of the system both in China and abroad and propose the development ideas, key tasks, and technical routes of the space Internet constellation system construction in China. To improve the service abilities of China’s space information network and establish a flexible space system, we suggest that China should strengthen top-level planning at the national level in the design and engineering construction stages, accelerate the exploitation of space and frequency resources, formulate satellite Internet standards, intensify efforts to tackle key technologies, promote integrated and innovative applications, and build a network security and protection system.