Objective: Patients with COPD have a lower overall quality of life than normal people. If patients with COPD do not regularly perform physical activities, their exercise capacity is reduced. It could lead to muscle loss, and negatively affect their general physical, social, and psycho-social status. The purpose of this study was to examine association with physical activity, sedentary life time and health-related quality of life in patients with COPD. Method: Of the total of 22,948 participants surveyed in Korean National Health and Nutrition Examination Survey (KNHANES 2013-2015), 8,626 participants were used for this study. Of these, under 40 years, over 80 years, missing values and abnormal values were excluded. Study variables included physical activity level, sedentary time and health-related quality of life variables. The physical activity level assessment tool was measured using International Physical Activity Questionnaire (IPAQ). Sedentary time referred to the amount of sitting time without moving the body. EQ-5D (Euro Quality of Life-5 Dimensions) was used as an index of health-related quality of life. Control variables were age, gender, income level, education level, marital status, comorbidity, smoking, BMI, cough, sputum, COPD severity. For this study, descriptive analysis, T-test, ANOVA and multivariate regression analysis were performed. Results: Of the 1,092 patients with COPD, 76.1% (n=831) were male and 23.9% (n=261) were female, while 39.0% (n=2,939) were male and 61.0% (n=4,595) were female in the comparison group without COPD. The COPD group with high level of physical activity showed a high level of EQ-5D scores ($0.9349{\pm}0.11$, p <0.001). Among patients with COPD, after adjusting for control variables, physical activity and sedentary time (physical activity level, Β=0.047, p <.001), (sedentary time, Β=-0.017, p <.05) were associated with health-related quality of life. Conclusion: Patients with COPD have a higher quality of life as their physical activity increases and the quality of life decreases as the time spent sitting increases. This study suggests that public health experts should consider improving COPD patient physical activity.