Polygonatum cyrtonema is a medicinal plant and its polysaccharides are used for immunomodulation and the treatment of hypoglycemia. Investigation of the tissue distribution and pharmacokinetics of P. cyrtonema polysaccharide can further elucidate its pharmacological mechanism. A fluorescence labeling approach using rhodamine B (RhB) as a fluorescent molecular probe was used for the quantitative assessment of the polysaccharide from dried P. cyrtonema (DPC1) samples, and the pharmacokinetics and tissue distribution of DPC1 were evaluated in mice after intraperitoneal or oral administration. DPC1 was successfully labeled with RhB, showing degrees of fluorescence labeling at 0.453% and 0.568% as determined by the ultraviolet and enzyme marker methods, respectively. DPC1-RhB was rapidly absorbed into the bloodstream after oral and intraperitoneal administration. The relative bioavailability of DPC1-RhB was as high as 48.648%, showing linear pharmacokinetic characteristics. After administration, DPC1-RhB was primarily distributed in the tissues of the heart, spleen, and lung, indicating that the drug has a targeted effect on these tissues. Overall, the findings provide a comprehensive reference for the in vivo distribution of DPC1, together with a foundation for further elucidation of its pharmacological mechanism and the development and application of DPC1 formulations.