Main compositions of ballpoint inks were determined by analyzing some tropical Fourier Transform Infrared(FTIR) spectra of 108 kinds of ballpoint inks. By using this method, the blue ink samples have been divided to two groups, 18 species depend on their spectral characteristics such as peak location, peak intensity. The reaction mechanism of age changes due to aging of the ink's compositions was discussed. The study is the first step for establishing the analytical date base of ballpoint inks system and estimating the age of ballpoint in written text has been offered. The advantage of this method is fast, reliable and nondestructive.