Trabala vishnou gigantina Yang (Lepidoptera: Lasiocampidae) is a polyphagous forestry pest whose periodic breaking out results in great economic damage including total crop failure to forestry and fruit production in China. In this study, in order to improve the understanding of the host plant selection mechanism of T. vishnou gigantina larvae, locust, caragana, willow, poplar, apricot and sea-buckthorn were used as potential host plants for the test. Two-way choice experiment method was used to study the T. vishnou gigantina Yang feeding preferences of the six kinds of plants. Moreover, the chemical component and physical structure of six plants were analyzed with Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). Among the six plants, T. vishnou gigantina larvae showed a strong preference for sea-buckthorn, followed by, apricot, willow, poplar, locust, and caragana. The FTIR analysis displayed that those six plants presented similar characteristic on absorption peak position, peak amount, and shape. The targets (1 154/1 733, 1 154/898) by FTIR showed that lipids and polysaccharide were major nutriments to affect the host plant selection of T. vishnou gigantina larvae. The XRD results showed that crystallinity index (CrI) also could affect the host plant selection of T. vishnou gigantina larvae. In this research, spectroscopy technology was firstly applied to the study of interactive relationship between insect and host, which would blaze a trail for intensive study of host plant selection mechanism of insect at molecular level.