The Monte Carlo method has been used to simulate the process of electron transport and acceleration in a nano-dimensional unit when irradiated by laser pulse of wavelength 1064 nm and power density of GW/cm2 level. When electrons transport in laser field, the scattering of electron-phonon and electron-surface are considered. The results show that: when the size of simulation unit is small to a degree, electron-surface scattering will dominate the scattering process and the small size effect becomes obvious. As a result, the electron is difficult to absorb laser energy. Based on the results, we can design new kind of films with nanostructure and improve the laser induced damage threshold of optical films.