Abstract: Urban disease refers to the urban population， industry， transportation and other malpractices caused by excessive concentration . It brings a lot of trouble and inconvenience to the people living in the city，and also has some undesirable effects on the operation of the city，so people call it "urban disease". According to the data of Beijing statistical yearbook ，the writer adopted the principal component analysis theory，with the help of MATLAB ，to study the problems related to the urban diseases in Beijing City and the establishment of Xiong′ an District，and then the writer put forward some suggestions for scientific and reasonable city planning.

Key words: urban disease, principal component analysis, Beijing City, Xiong′an District