Objective To investigate the risk factors of CT enhanced scan contrast agent nephropathy and the effect of hydration intervention. Methods The clinical data of 240 case of patients who underwent coronary angiography in our hospital from January 2015 to January 2018 were randomly divided into two groups, A group and B group. Among them, group A(120 cases) was given hydration intervention, B group(120 cases) was not given hydration intervention. 110 patients with no CIN in A group were into the control group, and 30 cases of CIN in group B were into the observation group. The basic information of all patients was analyzed, and the occurrence of CIN in the observation group and the control group was analyzed. Results 50 of the 240 patients had CIN, and the incidence was 20.83%. There was no difference between the two groups in the dose of contrast medium and the level of serum creatinine(P>0.05), and the cystatinC of the observation group was lower than that of the control group (P<0.05). The rate of coexistence of coronary heart disease, diabetes, hypertension and congestive heart failure of the observation group was significantly higher than that of the control group (P<0.05). Congestive heart failure, diabetes, baseline cystatinC, and baseline serum creatinine were independent risk factors for CIN (P<0.05).110 of the patients in the control group had no CIN, and the proportion was 91.67%. 90 of the patients in the observation group had no CIN, and the proportion was 75%. Conclusion The use of contrast agents can effectively prevent CIN after full hydration, and congestive heart failure, diabetes, baseline cystatin C and baseline serum creatinine are the the risk factors for CIN. The serum cystatin C can predict the intensity of CIN higher than the serum creatinine.