This paper deals with a system of taking quantitative measurement and economical evaluation of hydro-ecological benefits of forest which consists of three scopes of regional extents and throe categories of technical methods, namely (1) analysing the present data by means of computer DJS-121 to establish mathematical models on a vast scope such as the whole nation or a whole province, which may be combined with the work of forestry zoning in the same scope. An example of Heilongjiang Province is offered in this paper; (2) making an expedition to a tree farm or a forest area for the purpose of developing multiple-use forestry, which must be carried on in place practically, here we put forward [an example of Zhuting Forest Area, Zhuzhou County, Hunan Province; (3) setting up a fixed long term experiment station in various small watershed or some typical forest communities, from which scientific parameters of quantitative measurement and economical evaluation can be obtained. Here we hold out some examples such as a forested watershed and a wilderness watershed, as well as a Pinus massoniana stand and a Quercus acutissima stand. It is obvious that they can be mutually complementary and check each other. A forest-soil type is a basic functional unit in taking quantitative measurement and economical evaluation of hydro-ecological benefits of a forest. It is necessary to have a good forest situation along with a deep soil zone to support a satisfactory conservation capacity of water supply in a forest ecosystem. Based on storage capacity of gravitational water with reference to infiltration rate, we grade the forest-soil types into five different grades of conservation capacity of water supply respectively.