Through analyzing the two common evaluation indexes of intersection traffic condition,consist of intersection traffic capacity and intersection saturation degree,and on the basis of determining service level of each directional traffic line,the feasibility of grade crossing be separated can be determined comprehensively according to the position of grade crossing in the urban density area.

This paper analyzes on the theoretical foundation of the tighten city morphology and the problems existing in it, and points out that only controlling the urban density in a rational scope could implement the sustainable development of the city.

With the further developments of holiday-oriented tourism circle around Beijing and of regional tourism cooperation by Bohai bay area,the tourism spatial structure must take place by the driving force o.