Abstract: The relationship between the permeability coefficient and lapse of time was investigated by the simulated experiments. The effect of lapse of time on the permeability coefficient of the leachate collection system and the diameter of crystallization metacolloid was analyzed by using the leachate collection system composed of geotextile, MSW incinerated ash and gravel. The results show that the adhesion crystals on geotextile were growing to become more compact between crystallization metacolloids with increasing of the lapse of time because of the crystallization of calcium carbonate and calcium aluminate,the permeability of leachate collection system became small. Based the experimental results, the density of waste is not high to be advantageous for permeability when the MSW incinerated ash is compacted.