With Fourier transform of infrared spectroscopy and smart performance sampling, 50 plastic woven bags of different types and different places were analyzed. According to different absorption peaks of infrared spectra, the polymer material (plastic bag) samples were divided into two categories. According to the peak number, peak position, peak shape and relative peak height ratio, we can distinguish each type of sample. At the same time we test the repeatability of the method and the minimum detectable amount. This method does not destroy samples under inspect and has good repeatability. Therefore, it can be used to characterize polymer materials (plastic woven bag）.