In recent years, satellite terrestrial integrated networks (STIN) have become crucial global communication infrastructure, playing irreplaceable roles in emergency response. However, their open architecture and dynamic nature expose them to security threats like identity spoofing and data eavesdropping. While current solutions have flaws, including single-factor authentication vulnerabilities and centralized architecture risks. In this paper, we propose a lightweight authentication protocol featuring security and dynamic key management. It integrates Physical Unclonable Functions (PUF), biometrics, and lightweight cryptography with hash-chain-based key updates. Formal verification under the Random Oracle Model (ROM) confirms the protocol resists ephemeral secret leakage and machine learning attacks while balancing anonymity and traceability. Compared to existing schemes, it maintains strong security while significantly reducing computational overhead, offering an efficient solution for STIN authentication.