Trace elements play very important roles in biological organism and are closely related to many diseases. New analytical methods are urgently needed for in situ determination of trace elements in biological tissues or single cells. A method based on laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was developed here for in situ analysis. Line ablation mode was chosen and the output energy of the laser was optimized at a low fluence of less than 1 J cm(-2). Two kinds of elemental image of both a coronal section from mouse brain and single cells exposed to gold nanoparticles were obtained by the developed method. Due to the unique characteristic, such as good spatial resolution, excellent detection limit, and reasonable running cost, LA-ICP-MS will be applied widely and become a useful tool in biomedical research in the future.