2 1 1 189。 Southeast University (Jiulong Lake Campus) is located at No.2, Southeast University Road, Jiangning District, Nanjing, Jiangsu Province. According to the national postal code database, the postal code of Southeast University is 2 1 1 89, of which the first two "21"stands for Jiangsu Province, the third "1"stands for Nanjing, and the fourth.