To measure the molecular size of cellulose between parenchymal tissue and vascular bundle in bamboo, in this research, the molecular weight of parenchymal tissue cellulose (PTC) and vascular bundle cellulose (VBC) extracted from parenchymal tissue and vascular bundle were determined by CED viscosimetry. The results showed that the VBC polymerization degree was 1001, and the viscosity average molecular weight (Mη) reached 1.6×10~5, much higher than that of PTC molecular’s. Meanwhile, the obtained results were compared with the XRD results, th...