Along with the development of urbanization and the improvement of people's living standard, the domestic sewage is dramatically increased through time, resulting in serious environmental deteriorating in the water body. In order to decrease the pollution of surrounding water environment, the sewage treatment approaches through lands have been developed quickly and widly used. One of the most successful method is the slow filtering eco-treatment system, which lets sewage to go through the land planted with vegetation so that the sewage can be purified via flowing through the soil system. However, due to the high NaCl content in the domestic sewage, this treatment method may bring negative effects on the soil and plant. Accordingly, the hydraulic loading rate is the key parameter in slow filtering eco-treatment for the health of soil system and plant growth. To get a scientific and rational hydraulic loading rate is critical for sewage dispose and usage in land system. Therefore, our objectives are to evaluate the impacts of sewage through slow filtering eco-treatment system on soil properties and poplar growth, as well as to choose a suitable hydraulic loading rate for poplar plantation. The slow filtering eco-treatment system for sewage treatment was carried out with five hydraulic loading rates (0, 3, 6, 9, 12, 15 cm/week) from 2008 to 2009 in Longhu town, Zhengzhou City, China. The aboveground biomass growth and the physicochemical properties of topsoil (0-40 cm) and subsoil (40-100cm) were investigated during the experiment duration. Eight soil properties were investigated, such as soil organic carbon (SOC), soil nitrogen (N), soil phosphorus (P) and soil potassium (K) and etc. In order to simplify the comparison of the differences in soil characteristics, an comprehensive quality index (QI value) was used for topsoil layer, while the subsoil properties were analyzed with the single soil physicochemical property. Our results showed significant differences in the effects of loading rates on soil quality and poplar growth. The QI value of topsoil and the poplar aboveground biomass increased along with the hydraulic loading rate increasing between the rates of 3 to 9 cm/week, and reached the maximum at 9 cm/week. When hydraulic loading rate outpaced 9 cm/week, the topsoil QI value and the poplar aboveground biomass growth decreased along with the increased hydraulic loading rate. There existed significant positive correlation between topsoil QI value and the poplar aboveground biomass growth, indicating the topsoil QI value representing soil fertility change. Sewage disposal had little impacts on the subsoil properties as hydraulic loading rate below 9 cm/week but produced harmful effects on subsoil properties as hydraulic loading rate above 9 cm/week. The higher sodium ion contents in topsoil and subsoil were one of the main reasons to the reduction of soil quality and poplar aboveground biomass growth. According to above results, the slow filtering eco-treatment of sewage obviously impacts soil properties and poplar aboveground biomass growth. The soil properties change is significantly correlated with the poplar growth. And the suitable hydraulic loading rate for domestic sewage treatment by poplar land is 6-9 cm/week.