Abstract: Experimental research on single-event effects of double data rate (DDR) static random access memory (SRAM) with different feature sizes was carried out at 100 MeV proton cyclotron accelerator of China Institute of Atomic Energy. Single-event upset (SEU) cross-section curves with different proton energy and different incident angles were obtained for these SRAMs. The effects of incident proton energy and angles on the SEU saturation cross-section of SRAMs with different feature sizes were analyzed, and the SEU characteristics of 65 nm SRAM were simulated by Monte Carlo method. The results show that the SEU saturation cross-section decreases with the decrease of feature size, but the reduction is slowed down due to the increase of multiple-cell upset (MCU). The number of MCU increases with the incident angle, resulting in the increase of SEU cross-section of the device. The data-level interleaving technology used in the three kinds of SRAMs cannot effectively suppress the occurrence of multiple-bit upset (MBU).