Abstract: The Fully Depleted Silicon on Insulator(FDSOI) process is considered an ideal semiconductor technology for producing highly reliable aerospace electronic devices. Therefore, a comprehensive understanding of the single event effects mechanism in FDSOI devices is of theoretical significance for radiation-hardened design. This paper focuses on 22 nm FDSOI SRAM test devices and investigates the impact patterns and physical mechanisms of different heavy ions and electrical parameters on the sensitivity of Single Event Upset(SEU) in the devices. Experimental results indicate that in regions with high Linear Energy Transfer(LET) values, the proportion of Multi-Cell Upset(MCU) can reach 20%. Additionally, the core voltage has a relatively minor impact on the type proportion and occurrence probability of SEU. The incidence angle of heavy ions significantly increases the SEU cross-section of the devices, with a 130% difference observed when heavy ions are incident along parallel and perpendicular directions to the substrate well region. Therefore, when modeling Single Event Effect in FDSOI devices and designing for radiation hardening, it is imperative to consider the influence of non-direct diffusion charge sharing mechanisms and substrate potential distortion-triggered parasitic current mechanisms on the transient ionization charge collection process.