Objective： To analysis the values of microvolt T-wave alternans（MTWA） and maximum T-wave alternans（max-MTWA）in patients with low or moderate risk coronary artery disease（CAD），and assess the risk of sudden cardiac death（SCD）. Methods：One hundred and twelve CAD patients were enrolled for this study，and sixty-six non-CAD patients as the control group. Based on the Duke treadmill test scores（DTS），CAD patients were divided into 2 groups：the low-risk CAD group（with scores ranging from 5 to 15）and the moderate-risk CAD group（with scores ranging from-10 to 5）. All participants performed treadmill exercise stress tests and MTWA，max-MTWA and the heart rates（HR） at max-MTWA were recorded by the time-domain modified moving average beat analysis（MMA）method，then the ratio of max-MTWA/HR was calculated. Results：There were significant differences in max-MTWA，max-MTWA/HR ratio and MTWA values between the control group and the CAD group（all P＜0.05）. Furthermore，subgroup analysis showed that the max-MTWA and max-MTWA/HR ratio in the moderate-risk CAD group were higher than those in the low-risk CAD group，and the parameters in the low-risk CAD group were higher than those in the control group（all P＜0.05）. There was no significant difference in MTWA between the low-risk CAD group and the control group（P＞0.05）. However，MTWA in the moderate-risk CAD group were significantly higher than those in the low-risk CAD group and the control group（all P＜0.05）. Conclusion：max-MTWA and max-MTWA/HR ratio were significantly increased in patients with severe CAD. The risk of SCD in low-risk CAD patients was the low as the control group，while moderate-risk CAD patients have a higher risk of SCD.