The classifying of different designs is essential in the study of architectural style and the question of classification or systematic becomes very fundamental. This study explores the similarity between different architectural designs and proposes a classifying method which focus on the intrinsic relationship of spaces rather than the extrinsic form. Thus, a formation of style can be measured and treated scientifically. Three trials on 61 cases of Shanghai Lane Residence architectures with three different periods are performed to compare the results of traditional classification and the proposed classifying method. The result showed that (1) the formation of a style can be treated proportionally to the similarities of a inner spatial structure between designs, thus the connections between designs in different periods can be built. (2)through the application of 3 cluster analysis techniques: single linkage, complete linkage and Ward’s method, the design cases have been separated into different groups and the result shows Ward’ method has the most similar grouping with traditional way of architecture classification. (3) the phenomenon of family resemblance does exist between different designs, even between different classifications. (4)through the examine of social changes and the evolution of spatial forms, the effectiveness of architecture classification computation has been discussed and from the point of bottom-up, new designs often emerged from the old structures.