The methods of Single-Event Upset(SEU) rates calculation induced by protons on orbits are studied on nano device. The SEUs of 65 nm SRAM are tested by using heavy ions and protons generated by accelerator. The SEU rates induced by protons on orbit are calculated based on heavy ion and proton experimental data respectively. It is shown that the proton SEU rate obtained by heavy ion experimental data is 1.5 order of magnitude lower than that obtained by proton experimental data. The conclusion is that proton SEU test should be performed for nano device to evaluate its SEU sensitivity; and the proton SEU rate should be calculated based on the proton experimental data.