A simulation approach is developed to obtain the linear energy transfer(LET) spectrum of all secondary ions and predict single event upset(SEU) occurrence induced by neutron in memory devices. Neutron reaction channels, secondary ion species and energy ranges, and LET calculation method are introduced respectively. Experimental results of neutron induced SEU effects on static random access memory(SRAM) and programmable read only memory(EEPROM) are presented to confirm the validity of the simulation results. A simulation approach is developed to obtain the linear energy transfer (LET) spectrum of all secondary ions and predict single event upset (SEU) occurrence induced by neutron in memory devices. Neutron reaction channels, secondary ion species and energy ranges, and LET calculation method are introduced respectively. Experimental results of neutron induced SEU effects on static random access memory (SRAM) and programmable read only memory (EEPROM) are presented to confirm the validity of the simulation results.