Background: Studies put it there was an interaction between diabetes and abnormal blood pressure rhythm, and they both increased the morbidity and mortality of coronary artery disease (CAD). We aimed at analyzing the effects of abnormal rhythm (AR) of blood pressure (BP) and each kind of systolic or diastolic blood pressure (SBP, DBP) pattern on CAD in patients with type 2 diabetes in Southwest China. Methods: A retrospective cross-sectional study involved 853 type 2 diabetic patients with 24-hour ambulatory blood pressure monitoring divided into CAD and non-CAD groups through imaging examination of the coronary artery. SBP and DBP were divided into dipper (D), non-dipper (ND), reverse dipper (RD), and extreme dipper (ED) by nocturnal BP decline rate, respectively. The difference in mean 24-hour, daytime, bedtime SBP and DBP, and BP rhythm between groups was compared by variance analysis. The association between different BP rhythms and CAD was analyzed by multivariate logistic regression when adjust for clinical, laboratory, and BP parameters.Results: Most diabetic patients had non-dipper BP patterns in both CAD and non-CAD groups, while the CAD group had a higher percentage of RD in both SBP and DBP than non-CAD. More CAD occurred in RD-SBP than D-SBP (P<0.001), RD-SBP than ND-SBP (P<0.001), RD-DBP than D-DBP (P<0.001), and ND-DBP than D-DBP (p=0.006). AR-SBP (OR=1.622, P=0.015), AR-DBP (OR=1.774, P=0.001), RD-SBP (OR=2.320, P<0.001), RD-DBP (OR=2.140, P<0.001), ND-DBP (OR=1.648, P=0.006) were risk factors for CAD and those relationships were still significant after adjust for different parameters.Conclusion: Abnormal BP rhythm, especially reverse dipper pattern was a risk factor for CAD regardless of SBP or DBP in diabetic patients. While for non-dipper, only the non-dipper DBP pattern had a risky influence.