Abstract: ObjectiveTo investigate the alternation and clinical significance of reticulocyte and leucocyte in advanced non-small-cell lung cancer （NSCLC）before and after chemotherapy with Gemcitabine combining Cisplatin．MethodsThe reticulocytes were examined by Flow cytometry，and the leukocytes were examined by blood analyzer using the peripheral blood of 87 NSCLC cases in advanced patients before and after chemotherapy by GP regimen． ResultsOn the 6th，10th day after chemotherapy，leukocytes decreased progressively，lower than pre-chemotherapy significantly.On the 10th day leukocytes were significantly lower than the 6th day(P<0.01)，but the 14th day rebounded significantly comparing with the 10th day (P<0.01)，but still lower than the pre-chemotherapy level(P<0.01)；while reticulocytes on the 6th，10th day after chemotherapy decreased significantly than pre-chemotherapy (P<0.01)，however there was no significant difference between the 10th day than the 6th day (P>0.05)，while the 14th day rebounded significantly compared with the 10th day (P<0.01), regaining the pre-chemotherapy level (P>0.05)． ConclusionReticulocyte levels can be used as the more sensitive indicator in bone marrow suppression and restoration in advanced non-small-cell lung cancer after chemotherapy ，it deserves for clinical application after further investigations．