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Eight kinds of substrates were used in the experiment of the soilless culture. The water retention parameters, such as porosity, coefficient of permeability, water retention curve and diffusivity were measured. It was obtained that water diffusivity and water content of substrates conformed to empirical formula D(θ)=aebθand showed the variability of exponential function and high correlation coefficient. The perlite and vermiculite had high speed of water supply, but low water retaining capacity and irrigation efficiency. The total porosity of other six substrates except for perlite and vermiculite varied from 70% to 90%, and their water-air ratios were between 2.0～4.0. Therefore, they could be used as seedling and culture substrates. Based on the comprehensive matrix analysis, the result showed that the optimal ratio of peat and perlite was 2∶1, and that of peat, vermiculite and perlite was 3∶1∶1.