In this study, we try to produce SU-8 photoresist microstructure devices using nano-imprint technology, and try to conduct nano-indention tests on SU-8 photoresist with nano-indention detector, in order to describe the behaviors and characteristics of nano-indentions on SU-8 microstructure devices and establish the deformation mode for the indention under nano-meter level. The tests tell us that, after nano-indention tests, the result indention hardness increases with the loading rate, indention repeats, and reduction of load or depth. Similarly, the indention hardness decreases because of reduction of loading rate, extension of loading time, and increase of load, and depth. Finally, we propose a deformation mode for nano-indention. This mode can also be used to explain the deformation behavior of SU-8 under nano-indention.