Abstract：In order to avoid the blindness of the dimension tolerance and fit of the average diameter of the continuous isometric polygon profile by using the analogy method,to be aimed at characteristics of continuous isometric polygon profile formed by 2-dimension,it is analyzed that influence on angle parameters of the initial contact point of continuous isometric polygon profile connection is caused by combinations of differential tolerance and fit of two sizes. In order to minimize the contact force of the continuous isometric polygon profile,discriminant of reasonable or not of tolerance and fit of average diameter which is in middle of tolerance zone is established. The results of the examples show that better combinations of dimension tolerance and fit of both eccentricity( or double eccentricity) and average diameter can be obtained if dimension tolerance and fit of the eccentricity( or double eccentricity) can be firstly determined on the basis of the analogy method and then the dimension tolerance and fit of the average diameter is further determined according to the discriminant. So capability of load bearing of continuous isometric polygon profile connection can be increased.

Keyword：continuous isometric polygon profile connection;dimension tolerance and fit;selection method;initial contact point;