Abstract: The quality of writing is the primary issue in writing theory．“Analytic theory”is focused on typical hetots，weakening other factors；“reduetionism”consideres all factors，ignoring the relationship between factors；“wholism” boasts its where cognitive idea，being short of analytical method．It is universally acknowledged that the system theory is the best method to describe involved systems．The systematology says the system quality lies in its structure and function structure refers to the ways and orders through which the various factors within the system establish contacts and play functions and function which refers to the order and capability with which the system establishes contacts and play runetions with external enviomnment．This paper explores the quantity and quality between the various factors within the writ— ing system by a diversified way，presenting the order between the factors in term of nonlinear relation and of hierarchical structure．And the paper tries to set limited way of time and space，and to describe the contacts between writing and its emiroment，and to present their basic orders．