To observe the effects of modified Shenling Baizhu Powder on cough after lung cancer surgery，and to explore its related mechanism.Methods:A total of 142 patients with cough after lung cancer operation in Shaanxi Cancer Hospital from July 2013 to December 2017 were divided into a control group and an observation group according to random number table method，with 71 cases each.The control group was given compound methoxynamine orally，2 capsules per time，3 times per day; the observation group was given Shenling Baizhu Powder on the basis of the control group，one dose per day，200 mL warm decoction.Two groups were treated for 2 weeks continuously.After the treatment，the changes of clinical efficacy，serum inflammatory factors(PCT，CRP，IL-6，IL-8，TNF-α)，lung function(VC，FEV1，FEV1/FVC，MMEF，PEF)and immune function(IgA，IgM，IgG，complement C3，complement C4)of the 2 groups were observed.Results: 1)Clinical efficacy：the effective rate of the observation group was 88.73%，which was significantly different from 74.65% of the control group(P<0.05). 2)After treatment，the LCQ-MC scores and total LCQ-MC scores of the 2 groups in different dimensions were increased than those before treatment(P<0.05)，and the rising trend of the observation group was more obvious than that of the control group(P<0.05). 3)Serum inflammatory factors：After treatment，the concentration of PCT，CRP，IL-6，IL-8 and TNF-α in peripheral serum of the 2 groups decreased compared with that before treatment(P<0.05)，and the tread of decrease in the observation group was more significant，with statistical significance compared with the control group(P<0.05). 4)Pulmonary function：After treatment，the concentration of VC，FEV1，FEV1/FVC，MMEF and PEF in the 2 groups increased compared with that before treatment(P<0.05)，and the improvement in the observation group was more significant than in the control group(P<0.05). 5)Immune function：After treatment，the levels of IgA，IgM，IgG，complement C3 and complement C4 in the 2 groups were significantly increased than those before treatment(P<0.05)，and the increase in the observation group was higher than that in the control group(P<0.05).Conclusion:Modified Shenling Baizhu Powder can significantly improve the clinical symptoms and lung function of patients with cough after lung cancer surgery，and its mechanism may be related to the reduction of serum inflammatory factors and the improvement of body immunity.