Objective To compare the effect of intravenous combined with oral hydration and routine hydration in the prevention of contrast induced nephropathy in patients with chronic renal insufficiency. Methods A total of 48 patients who were undergoing percutaneous coronary intervention or diagnosis were randomized divided into the short-time hydration group ( 25 cases ) and the conventional hydration group (23 cases). Patients in the short-time hydration group received intravenous hydration at 3 ml/(kg·h) from 1 hour before the operation to 4 hours after the operation, and oral hydration at 1 ml/( kg·h) rate from 4 hours before the operation to 10 hours after the operation. Patients in the conventional hydration group received intravenous hydration at 1 ml/( kg·h) from 12 hours before the operation to 12 hours after the operation. Levels of Serum creatinine ( Scr) and Cystatin C ( CysC) were measured 1 d, 2 d and 3 d preoperative and postoperative, and the incidence of contrast induced nephropathy between two groups was statistically analyzed.Results There was no significant difference in blood Scr, CysC of 1 d, 2 d and 3 d preoperative and postoperative and incidence of contrast nephropathy between two groups ( P>0. 05 ) . Conclusions The effect of short time intravenous combined with oral hydration and routine hydration in the prevention of contrast induced nephropathy has no difference in patients with chronic renal insufficiency.