Binding thread is an important component in bamboo strip relics. Because of its unstable properties, when unearthed, the thread is usually heavily degraded, or even missed, and is thus neglected by most researchers. Up to now no related scientific analysis on this topic can be found in the literatures. However, some fragments of binding threads can be found in the West Han Dynasty and Qin Dynasty bamboo strips collected by Peking University. In order to characterize the material and the degree of deterioration of these objects and to provide reference for future research on and conservation of bamboo strips, a variety of techniques such as microscopic analysis of morphology, polarized light microscopy and histochemistry were employed to identify the species and chemical compositions. The results show that the two batches of binding threads studied are both made of ramie. The cellulose, hemicelluloses and pectin components are almost completely degraded. The lignin and fat/wax are retained, but the aldehyde functional groups in the lignin had changed. Several parasitic ova were found in Qin binding thread. These presumably belong to Clonorchis sinensis, in accordance with the epidemiology archives and burial customs in such regions.