Background. Patients with stable chronic obstructive pulmonary disease (COPD) have been observed to benefit from tiotropium bromide. However, there are few studies of tiotropium bromide on sputum and sputum viscosity. To evaluate the effect of tiotropium bromide on mucus hypersecretion, a randomized, double-blind controlled trial was performed. Methods. 120 cases of patients with pulmonary function grade II were divided into two groups, which include the treatment group given tiotropium bromide powder inhalation (18 μg, inhalation, QD) and the control group given formoterol fumarate powder inhalation (12 μg, inhalation, BID) plus ambroxol hydrochloride tablets (60 mg, oral, TID). After 3 months of treatment, the pulmonary function and α1-acid glycoprotein (α1-AGP) in sputum were detected, and the changes of glycoprotein and Ca2+ content were evaluated by Miller classification. Results. Three patients (2 cases in the treatment group and 1 case in the control group) were dropped due to loss of follow-up, and 117 cases of patients were enrolled in this study. After 3 months of treatment, the sputum character score, α1-acid glycoprotein, Ca2+ content, and lung function of the two groups were significantly improved; group comparison analyses revealed that there was no significant difference in the content of α1-AGP, Ca2+ in sputum, and lung function between the two groups (
P
>
0.05
), but the improvement of sputum properties was significant (
P
<
0.05
), and the treatment group was better than the control group (
t
=
−
2.77
;
P
=
0.007
). Conclusions. Inhaled tiotropium bromide can effectively inhibit the mucus hypersecretion in stable COPD patients, improve the sputum properties and lung function of patients, and improve the quality of life of patients.