Objective To assess inhaler technique among patients with chronic respiratory diseases in Southwest China, and identify key physiological and psychological factors affecting correct inhaler use. Methods This was a multicenter cross-sectional study. Inhalation operation technique was assessed using a self-developed scale. Inhaler proficiency of participants was assess by critical error occurrence, and the pass rate was calculated accordingly. Binary logistic regression was applied to identify factors associated with critical errors, including variables with P<0.1 from univariate analysis in a multivariate model. Variable selection was performed using a stepwise method. Results A total of 336 inhalation device users from 8 central hospitals in Sichuan Province were enrolled. The overall error rate of inhalation device use was 87.2%. Among dry powder inhaler users, 21.4% failed to achieve the inspiratory flow rate required by the device. Among pressurized metered-dose inhaler users, 35.71% were unable to achieve hand-mouth coordination after three operation attempts. Binary logistic regression analysis showed that forgetfulness experience (OR=0.389, 95%CI 0.156-0.970) and inspiratory flow rate (OR=0.977, 95%CI 0.964-0.989) had statistically significant effects on correct device use. No statistically significant psychological factors were identified in this study. Conclusions Incorrect inhaler use is highly prevalent among patients with chronic respiratory diseases in Southwest China, with many unable to meet the inspiratory flow requirements of their devices. Low inspiratory flow and operational forgetfulness may contribute to poor inhaler technique.