Abstract: The electron-stimulated desorption(ESD) process of NaCl has been studied by in situ high resolution transmission electron microscopy. The size of the NaCl crystal is decreasing with the decomposition rates on each NaCl surface similar. Many sodium colloids form around the cuboid shape shell, which may coalesce into large Na colloids as the ESD process goes on. Inside the NaCl crystal, abundant rectangular islands are distributed with a side length of 4-7 nm. Some of the corners are truncated with kink sites formed.Meanwhile, dislocations can be found inside the Nacl crystal. A hydrocarbon layer can decelerate the desorption process of NaCl thin film.