In this paper, the Am-241 is used as the alpha particle radioactive source to carry out the soft error mechanism and accelerated test technology research in 65 nm and 90 nm static random access memories (SRAM). Combined with reverse analysis, TRIM and CRèME-MC Monte Carlo simulation, the energy transport process, deposited energy spectrum and cross-section characteristics of alpha particles in the device are revealed. The results show that the soft error sensitivity of the 65 nm device is much higher than that of the 90 nm device, and no flipping polarity is found. According to the real-time measured soft error rate at an altitude of 4300 m in Tibetan Yangbajing area, thermal neutron sensitivity and alpha particle soft error rate, the overall soft error rate of 65 nm SRAM applied at sea level of Beijing city is 429 FIT/Mb, and the contribution of alpha particle is 70.63%. Based on the results of reverse analysis, a three-dimensional simulation model of the device was constructed to study the influence of the incident angle of alpha particles on the single event upset characteristics. It was found that the corresponding deposition energy value at the peak of the number of particles in the sensitive region, decreased by 40% with the incident angle from 0° to 60°. While the single event upset cross section increased by 79% due to the apparent single event upset edge effect in the sensitive region of the 65 nm device.