As the integration of Automatic Emergency Braking (AEB) system in autonomous vehicle systems becomes more prevalent, ensuring their safe operation in dynamic driving environments has become increasingly critical. AEB systems are a key part of intelligent driver assistance technologies, enhancing road safety by automatically applying the brakes to prevent or mitigate collisions. However, hazards can occur, when the system performs its intended function and is free from faults, highlighting the importance of Safety of the Intended Functionality (SOTIF). This paper analyses the SOTIF hazards of the AEB system arising from performance limitations and functional insufficiencies, utilizing the System-Theoretic Process Analysis (STPA) methodology. The operational structure of the AEB system is systematically analysed to identify control actions, unsafe control actions, potential causal factors, and the specific conditions that may trigger these unsafe actions. The results provide valuable insights into the safety implications of AEB system and support the derivation of improved safety requirements and design constraints to address the hazards. This paper provides a practical framework for conducting SOTIF analysis in autonomous and intelligent vehicle systems. By bridging the gap between theoretical safety concepts and real-world implementation, this work contributes to the development of safer and more reliable intelligent driving technologies.