As strategic minerals become increasingly critical in the competition among great powers, combined with high-quality development requests, their security issues gain more prominence. Based on an in-depth understanding of the connotation of China's strategic mineral security, this article developed a rare earth security assessment index system with 3 sub-objects: global supply stability, domestically economic security and coexistence, then conducted sensitivity analysis using Monte Carlo simulation. The results show that: (1) Global supply stability increased, then fluctuated and declined due to deficiencies in sustainable development and politics, affecting China's long-term rare earth security index; (2) Domestically economic security was weakening due to reduced mine supply, impacting China's short-term rare earth security index; (3) The coexistence index was rising, influenced by industry chain security changes, with increases benefiting China's rare earth security index; (4) China's rare earth security level rose from 2010 to 2022, tracking the coexistence index, indicating that international market integration boosts rare earth security. Based on the above findings, the article puts forward corresponding policy implications.