The absorption coefficients of NO2 in the region from 500 to 1100 Å are measured by a photographic method using the radiation from electron synchrotron as a background source. For the Rydberg series due to the transition from 4a1 to npπ, parameters q and Γ in Mies equation are obtained and the parameter q is determined to be −0.4 for every member and Γ 4.808/n*3 eV where n* is the effective quantum number.The absorption spectrum of NO2 in the region from 600 to 1600 Å are also analyzed. New vibrational progressions that are observed around 950 Å, are assigned to the excitations from 4b2 to ns Rydberg states (n = 3, 4, and 5) converging to the 1B2 ionic state. Assignments and discussions of many other Rydberg series that appear in the absorption spectrum between 600 and 1600 Å are also presented.