Abstract：Infuenced by the modernization process of Beijing from 1949 to 1978, the urban morphology has transferred from ho-
mogeneous and horizontal into hybrid and multifarious. This paper analyses three kinds of diferent plan-units in Beijing,
which is further divided into eight prototypes, in order to reveal its morphological evolution mechanism. It has been found
that the evolutionary process is highly related to internal and external factors, and is infuenced by the plot ration and the
building density.
