Abstract: The preconcentrator is a front-end sampling and concentrating device that can significantly improves the detection limit of a microanalytical system. The micromachined preconcentrators with reduced thermal mass can raise the temperature much faster at lower power compared with the conventional desorption tubes, thus realizing a much higher concentration factor. In this paper, the state-of-the-art of the microfabricated preconcentrators are systematically summarized, with especial emphasise on the structure of the micro-preconcentrators from the point of view of adsorption area, gas flux, temperature rising, fluid channel design, and so on. The principles of phased heater array and preconcentrator with integrated micro-valves are also introduced.