Subak is a social organization in Bali that specifically regulates traditional water distribution system to grow rice. With the rapid development of this time, the existence of subak is threatened because of the conversion of land to other uses outside the agricultural sector which causes open green space to be increasingly reduce. Environmental services are the services provided by the ecosystem functions that have direct and indirect benefits to human welfare. This research analyzed to changes in soil quality in subak, in the conditions before planting and after harvest an to show subak contribution to the environment. This study used survey method, physical soil test in the laboratory. The samples were taken by random sampling, from Subak Kerdung, Subak Jatiluwih and Subak Lodtunduh. The soil qualities were assessed using scoring technique based on the physical parameters. The soil physical parameters observed were texture, porosity, field capacity, bulk density and particle density. The result of research showed that the change in soil quality on the subak land was be better. Contribution of subak can be seen from the physical soil parameters, that is increased porosity and decreased bulk density of subak. Subak Jatiluwih in the before planting phased had porosity of 56,27% and then 66,91% after harvest phase. The best change of bulk density in Subak Jatiluwih in the before planting phase is 1,05 g/cm3 and then decreased to 0,92 g/cm3 after harvest phase. Environmental services of subak system is able to maintain and improve the quality of the soil through theability to cultivate the soil.