To study the effect of Cynomorium songaricum polysaccharide (CSRP) on A549 cells telomere of human non-small cell lung cancer, the mice were intragastric administrated with CSRP (0.08 g•kg⁻¹) once daily for 4 days. Then their serum was taken for preparing CSRP drug serum. A549 cells were treated by