Aim To investigate the relationship between complement-C1q/TNF-related protein 13 (CTRP13), urinary microalbumin/creatinine ratio (UACR) and unstable angina pectoris (UAP) with type 2 diabetes (T2DM). Methods From October 2019 to October 0,0 patients who were hospitalized in the Department of Cardiology and Endocrinology of the Affiliated Hospital of Chengde Medical College were divided into UAP+T2DM group (n＝50), UAP group (n＝50) and T2DM group (n＝50) according to whether they were diagnosed with UAP and T2DM. Healthy people who underwent physical examination at the same time were selected as the control group (n＝50). Serum CTRP13 concentration and morning urine UACR level were measured in four groups. The general data and the differences of CTRP13 and UACR levels were compared among groups, and the correlation between CTRP13, UACR and various indexes was analyzed in UAP+T2DM group; The reciprocal f(CTRP13(ng/L))＝1/(CTRP13(ng/L)) was used to convert CTRP13. The predictive efficacy of f(CTRP13) and UACR on UAP+T2DM was analyzed by ROC curve. Results The level of serum CTRP13 was the lowest in UAP+T2DM group, followed by T2DM group and UAP group, and the highest in control group(P＜0.05). The level of UACR was the highest in UAP+T2DM group, followed by UAP group and T2DM group, and the lowest in control group(P＜0.05). The Gensini score of UAP+T2DM group was higher than that of UAP group. Correlation analysis showed that in UAP+T2DM group, the level of serum CTRP13 was negatively correlated with fasting blood glucose (FPG), high sensitivity C-reactive protein (hs-CRP) and Gensini score, and positively correlated with high density lipoprotein cholesterol (HDLC) (all P＜0.05); UACR was positively correlated with waist circumference, low density lipoprotein cholesterol (LDLC), hs-CRP and Gensini score (all P＜0.05). The ROC curve showed that the areas under the curve (AUC) of f(CTRP13) and UACR single detection and combined detection of UAP combined with T2DM were 0.820 (95%CI:0.759～0.882), 0.846 (95%CI:0.786～0.905) and 0.876 (95%CI:0.820～0.931) respectively; their sensitivities were 88%, 82% and 86%, respectively; and their specificity were 64%, 80% and 77.3%, respectively (all P＜0.05). Conclusions CTRP13 and UACR may not only be used as auxiliary indicators for clinical diagnosis of UAP complicated with T2DM, but also can be used to evaluate the severity of coronary artery disease. The combined detection of both of them is of higher value in the diagnosis of UAP with T2DM.