Objective: To describe the characteristics, etiology and patterns of outpatients and inpatients patients with moderate or severe valvular heart disease (VHD). Methods: This is a cross-sectional study. Outpatients and inpatients with moderate or severe VHD who underwent transthoracic echocardiography for first examination from 1st January 2001 to 1st January 2020 in Southwest Hospital, Army Medical University were enrolled. Data were collected from medical records and big data platform of Southwest Hospital. Characteristics of age and gender, etiology and types of VHD were descriptively analysed. Results: A total of 68 354 patients with moderate or severe VHD were enrolled. The age was 63 (50, 72) years. And 35 706 (52.24%) patients were female. (1) Age characteristics: There was similar age trend between male and female patients with moderate or severe VHD. The number of patients increased firstly and then decreased and reached its peak in the age group of 65-69 years old. The peak age of mitral stenosis patients was 45-49 years, which was earlier than that of whole patients with moderate or severe VHD. The median age of patients with bicuspid aortic valve was 42 years. (2) Gender characteristics: The proportion of tricuspid regurgitation, pulmonary regurgitation, mitral regurgitation, mitral stenosis and valve surgery in female patients with moderate or severe VHD were higher than those in male patients. The proportion of aortic regurgitation, aortic stenosis and bicuspid aortic valve in male patients with moderate or severe VHD were significantly higher than those in female patients (all P<0.05). (3) Etiology: The proportion of rheumatic VHD was 13.07% (8 934/68 354), which was higher than that of degenerative VHD (0.67% (458/68 354)). (4) Types of VHD: Tricuspid regurgitation made contribution to the largest proportion with 60.72% (41 503/68 354), followed by mitral regurgitation, aortic regurgitation, mitral stenosis, pulmonary regurgitation and aortic stenosis. Conclusions: There are certain regional characteristics in the prevalence of moderate or severe VHD in southwest China, suggesting different attention should be paid on the whole process of refined management of moderate or severe VHD.