Stable COPD patients were divided into four levels of A, B, C and D by a comprehensive assessment system, with the horizontal coordinate using respiratory system scores, including MRC scores and CAT scores; MRC scores <2 belonged to group A; CAT scores >10 belonged to group B; the vertical coordinate was classified as position C and D according to the number of acute exacerbations, with more than 2 acute episodes within one year; the acute incidence was less than 2 times within one year The risk level is lower. In addition, the one-second volume <70% was used as the diagnostic criterion, and it was classified as mild, moderate, severe, and very severe according to specific values. The grading was to facilitate further treatment and management, and different inhaled bronchodilators were applied according to different levels.