Based on the temperature data of the atmospheric boundarylayer below 500m in the northern suburbs and outskirts of Nanjing,the temperature profile in different degrees of stability is analysedand fitted. It is shown that the logarithmic-linear law is good in precision and there also exists an inversion centre in the lower boundarylayer in the flatlands. The thickness evolution model of nocturnalrdiation inversion suggested by Anfossi is found to be applicable.