Abstract: A series of water retention tests, gas permeability and diffusion tests are conducted to investigate the water content, water loss rate, gas permeability K_p and gas diffusion coefficient D_p of CCL with different modified amounts of PAM. The results indicate that the water content increases with the increasing amount of PAM, the water loss rate exhibits an opposite trend, and the water retention performance is better than that of the ordinary agroforestry water-retaining agent with the dosage ranged from 0.8% to 1.0%. The gas permeability and gas diffusion coefficient decrease with the increasing amount of PAM. When the content increases from 0 to 1.0%, K_p decreases by about one order of magnitude, and D_p is 35% of the original one.