Abstract: The concept of environmental bearing capacity capability is advanced on the base of integration between en-vironmental capacity and carrying capability, it embodies the comprehensive structure, function and feature ofenvironmental system. Urban environmental system is the most complicated one on the earth, it has many func-tions and actions such as service, restrict, safeguard, efficiency, adjust, convey and purify.
Environmental capacity is the biggest allowed loading quantities of the pollution discharged by other systemsand bear by essential elements of environmental system, it involves three aspects of environmental function dis-trict, quality and quality standard, and possesses three features of objectivity, relativity and capable of definition; environmental carrying capability is the biggest supported threshold value of the resources of environmental sys-tem could bear the regular running of the ecology and human systern, it has objectivity, relativity, statistic and ca-pable of adjustment. Environmental capacity reflects the natural property of environmental system, that is its in-ner endowment and specific characteristic, and emphasizes on the its qtality measurement; Environmental carry-ing capability highlights the synthetical function of environmental system, that is its outer sustaining ability to ofecology and human system, and stresses on the quantity estimation.
The calculation of urban environmental capacity firstly must determine the effective scales of essential ele-ments (atmosphere, water and land) of environmental system, and secondly choose the environmental quality standard; The measurement of city environmental catrying capability need to judge the total amounts of environ-mental resources on one hand, and to draft the human developmental standard on the other hand. The concretemethod could be used have regression model and input-output model etc.

Key words: environmental bearing capacity, urban environmental systerm, measuring methods