Abstrat Small watershed is a complexed system of ecology and economy

of which the ecological system has exchange of energy

material and information with the external and could absorb negative flow of entropy

which makes the system leave balanced stable and tend to the ordered structure of the economy system man power and natural resource play predominant effects on the complexed system of ecology and economy

it is thought that to coordinate the relationship between human activity in society and economy

it is thought that to coordinate the relationship between human activity in society and economy and the economy

it is though that to coordinate the relationship between human activity in socitety and ecology and economy

it is thought that to coordinate the relationshio between human activity in society and economy and the ecological system is the fundamental problem for the harness of small watershed.Only when approaching from the factors of nature and social economy and their regineering like dynamic simulation of system and ecological principle

and finding the key problems in the system through a series of logical and nathematical analysis

might it be possible to design harness plan and dispoes the measures.It is said that the ultimate goal to harness small watershed is to establish a stable

enduring and effcient system of ecology and economy