Geological sequestration can be used to reduce CO₂ emission without much effect on economic growth. It has become an indispensable technical approach to achieving dual-carbon goals. However, geological sequestration carries significant environmental risks from CO₂ leakage at storage sites. To ensure the safety and efficacy of carbon sequestration it is critical that potential leaks can be identified through continuous monitoring. In this regard, the Internet of Things (IoT) is ideal due to its large-scale, continuous monitoring, and intelligent analysis capabilities, yet this technology has not been widely implemented. This paper outlines the basis for sensor selection and sensor node deployment, proposes the design idea for underlying sensor technology, and establishes an IoT CO₂ monitoring system for storage sites. Specifically, infrared CO₂ sensor is selected as the primary sensor and laser CO₂ sensor as the secondary sensor, along with FT-IR patrol monitoring; a combination of real-time optimization of mobile deployment, random deployment, and fixed deployment is used in sensor node deployment; a mix of cluster topology and mesh topology is used in high-risk areas, and star topology and tree topology are used in edge areas connected to the main area. As technology advances, sensor mass production and sensor miniaturization will lead to more efficient and scalable sensor networks, and IoT monitoring technology will play a crucial role in continuous monitoring of carbon storage sites.