With the advancement of 5G and terahertz communication technology, there is a growing demand for high-capacity and low-latency wireless communication in subway environments. However, typical complex indoor settings such as subway waiting halls suffer from severe multipath effects and signal blockages, leading to insufficient wireless coverage and signal degradation. This paper proposes a hybrid Internet of Things(IoT) coverage enhancement scheme based on Reconfigurable Intelligent Surface(RIS). Using a ray-tracing method, the subway waiting hall is simulated to identify areas with weak coverage. To address the issue of insufficient wide-area coverage, a reconfigurable intelligent surface operating in the 2.6 GHz frequency band is employed to enhance coverage, effectively improving the link quality between base stations and weakly covered areas. The results demonstrate that the proposed method significantly enhances communication performance in complex waiting hall environments, reducing blind spots and increasing system capacity. Furthermore, to meet the high-rate demands in hotspot areas, a terahertz-band RIS is introduced for local enhancement. This hybrid RIS cooperative scheme ensures broad coverage while simultaneously supporting high data rates and low latency, providing an efficient and flexible solution for improving IoT link quality in subway scenarios.