Objective To evaluate the early prognostic value of quantitative detection of cardiac troponin I（cTnI）in patients with unstable angina pectoris（UAP）.Method 88 cases of UAP patients in the observation group and 54 cases of healthy people in the control group were tested serum cTnI and creatine kinase（CK-MB）and the incidence of cardiac events in the observation group was observed.Results The average quantitative determination of cTnI was（0.34±0.02）ng/mL in the observation group

that of the control group was（0.01±0.00）ng/mL and the difference between the two groups was statistically significant（P<0.05）;the difference of CK-MB levels in the two groups was not statistically significant.Among the 88 cases of UAP patients

35 cases were detected positive for serum cTnI（cTnI≥0.1ng/mL）

53 cases were detected negative for serum cTnI（cTnI<0.1ng/mL）.The incidence of acute myocardial infarction

cardiac death and intractable angina during hospitalization was 82.9%in UAP patients with cTnI positive

the incidence for UAP patients with cTnI negative was 18.9%and the difference was statistically significant（P<0.01）.Conclusion CTnI is a biochemical index reflecting high sensitivity and specificity of myocardial cell injury and the quantitative determination of cTnI has a good predictive value for early prognosis of UAP patients.