Objective:To identify the prevalence of multimorbidity among a Chinese population, analyze the risk of all-cause mortality with different multimorbidity patterns, and the impact of exercise on the risk of multimorbidity-related mortality and life lost.Methods:The study was based on 437 408 MJ Health Management Center participants. The classification decision tree was used to explore multimorbidity patterns composed of hypertension, diabetes, chronic kidney disease (CKD), and chronic obstructive pulmonary disease (COPD). The Cox proportional hazards model was used to calculate the all-cause mortality hazard ratio ( HR) for different multimorbidity patterns. Using Chiang's life table method, years of life lost were the difference in life expectancy for those with and without multimorbidity. Results:The prevalence rate of multimorbidity was 8.7%. Among multivariate patterns, the most common ones were "hypertension+CKD" (3.6%), "hypertension + diabetes + CKD" (1.1%) and "hypertension+diabetes+CKD+COPD" (0.1%). Compared with a healthy population, patterns with the highest mortality risk were "diabetes+CKD" ( HR=3.80, 95% CI: 3.45-4.18), "diabetes+CKD+COPD" ( HR=4.34, 95% CI: 3.43-5.49) and "hypertension+ diabetes+CKD+COPD" ( HR=4.75,95% CI:4.15-5.43). Through low-intensity and moderate to high-intensity exercise, the increased HRs were attenuatedcompared with the inactive population. People with single disease and multimorbidity shortened life by 4.6 and 13.4 years, while exercise attenuated 2.3 and 4.6 years of life lost, of which low-intensity and moderate to high-intensity exercise saved 1.5 and 3.7 years of life lost due to chronic diseases. Conclusions:Multimorbidity patterns based on "diabetes + CKD" cause the highest mortality risk, and physical activity in reducing mortality was significant for either with or without multimorbidity. Higher exercise intensity leads to a greater relative reduction of mortality risk.