Objective: To probe the effect of graded cardiac rehabilitation care on clinical efficacy and quality of life in patients with severe coronary heart disease (CHD) after treatment with off-pump coronary artery bypass (OPCAB). Methods: Data of 100 patients with severe CHD treated by OPCAB from February 2020 to August 2021 in Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology were retrospectively collected. Based on the nursing methods, 52 patients who receiving graded cardiac rehabilitation care were divided to an observation group, and 48 patients receiving conventional cardiac rehabilitation care were divided to a control group. Clinical efficacy, cardiac and pulmonary functions, exercise endurance, quality of life, and adverse cardiovascular events were assessed after 6 months of rehabilitation. According to the prognosis, the patients were divided into a poor prognosis group and a good prognosis group. The risk factors of adverse cardiovascular events affecting the prognosis of the patients were analyzed by logistic regression. Results: The total effective rate of rehabilitation in the observation group was higher than that in the control group (80.77% vs. 58.33%, P<0.05). After 6 months of rehabilitation, the improvement of cardiac function and pulmonary function in the observation group was better than that in the control group (P<0.05). In addition, the exercise endurance, quality of life and health status in the observation group were better than those in the control group (P<0.05). After six months of follow-up, it was found that the incidence of adverse cardiovascular events in the observation group was lower than that in the control group (P<0.05). Unconditional classification logistic regression analysis showed that diabetes, left ventricular ejection fraction (%) <= 50, left main artery disease, and type C disease are risk factors for adverse cardiovascular events after OPCAB in patients with severe CHD (P<0.05). Conclusion: After OPCAB treatment for severe CHD, graded cardiac rehabilitation care can improve nursing efficacy, promote the recovery of cardiopulmonary function, improve exercise endurance, quality of life and health status, and reduce the incidence of adverse cardiovascular events in patients. Diabetes, left ventricular ejection fraction, left main artery disease, and type C disease were independent risk factors for adverse cardiovascular events.