40Ar/39Ar thermochronology has been one of the most powerful tools for researching thermal history of geological body owing to the fact that, for Ar isotopic system, closure temperatures of minerals for dating spread a wide range and that non-linear cooling history between 650 ℃ and 150 ℃ could be obtained. However, some problems with respect to the mechanisms for argon diffusion in these minerals have not been completely understood which restricts the development of 40Ar/39Ar thermochronology to a certain extent. Two most widely used models, multiple diffusion domain models and multipath diffusion model will be introduced here, including their actualities, problems and possible solution, and the trend of 40 Ar/39Ar thermochronology.