Abstract:In airport location stage, different site’ clearance condition lack of quantitative methods for the comparison. In order to solve this problem, the quantification method was studied from degree and scope of the influence of the obstacle to the clearance condition. Firstly, the definition of obstacle's own attribute and the concept of obstacle's influence degree were put forward, and five indexes which include position of obstacle, physical characteristics, superelevation, slope, projection area were constructed to evaluate the influence of obstacle's own attribute to the clearance condition, and five indexes’ quantitative expression method, weight and obstacle's influence degree calculation method were given. Secondly, based on the principle of obstacle shelter in the clearance area, the method to determine the influence range of obstacles in different areas of the clearance area was established; Thirdly, the concept of the influence rate of obstacles was put forward and the calculation method was given based on the revision of the influence range of obstacles by the influence degree. Finally, to comparison of the clearance conditions of the two airport sites to be selected, the model and method of this paper were used to calculate, and the quantitative comparison results were obtained. Through the above research, a quantitative method for comparing the clearance conditions at the airport site selection stage is established, which provides a new way of thinking and method for judging the advantages and disadvantages of the clearance conditions.