Objective To observe the effect of different elevation angles of lower limbs on comfort level of patients during leg vein graft harvesting for coronary artery bypass grafting (CABG). Methods Totally, 120 patients after CABG performed with prior leg vein graft harvesting were randomly divided into either of the 3 groups of 40 cases each with the affected leg elevated to various angles: the 20° group, the 30° group and the 40° group （38 cases completed the study）. The degree of swelling, comfort score, pain score and complication rate of the affected leg were observed 2-5 days after operation. The differences in the three groups were compared by running repeated measures analysis of variance. Results The degree of swelling, comfort score, and pain score observed at various time points showed significant differences （P<0.05 for all）, with the 40° group having the mildest swelling, and the 30° group having the highest comfort scores versus the lowest pain scores. Complication incidence rate of the affected leg showed no significant difference among the 3 groups （P>0.05), though the 30° group had the lowest incidence rate. Conclusion Though the leg elevation in the 30° group had more severe leg swelling than the 40° group, it outperformed others with highest comfort scores, the lowest pain scores, and the lowest incidence rate of complication. In view of patient comfort and clinical effect, leg elevation at 30° is recommended to patients after CABG performed with prior leg vein graft harvesting.