Apoptosis is recognized as an important mechanism in contrast-induced nephropathy (CIN). This study investigated the renal protective effect of cordyceps sinensis (CS) in a diabetic rat model of CIN and the mechanism of its effect. Sixty SD rats were randomly divided into 4 groups, the control group, model group, probucol group, and CS group. We used a diabetic rat model of Iodixanol-induced CIN. Serum creatinine (Scr), blood urea nitrogen (BUN), urinary kidney injury molecule-1 (KIM-1), neutrophil gelatinase associated lipocalin (NGAL) levels were measured to evaluate renal function. Total antioxidative ability (T-AOC), superoxide dismutase (SOD), and malonaldehyde (MDA) levels were assessed to discuss the effect of probucol and CS on oxidative stress. The pathologic changes in the kidney were observed by hematoxylin and eosin (HE) staining and periodic acid-Schiff (PAS) staining. Apoptosis was assessed by transmission electron microscopy and TUNEL staining. Caspase-3, Bax, Bcl2 and phospho-p38 mitogen-activated protein kinase (MAPK) protein expressions were assessed by Western blotting. The model group of rats showed significantly elevated levels of BUN, Scr, urinary KIM-1, NGAL, and parameters of oxidative stress (P<0.05). Both the probucol and CS groups demonstrated significantly lower Scr, BUN, and urinary KIM-1, NGAL levels compared to the model group (P<0.05), with no significant difference between these two groups. The probucol group and the CS group had significantly lower MDA and higher T-AOC, SOD than the model group after modeling (P<0.05). Caspase-3, Bax activation were effectively repressed while Bcl-2 expression was increased by probucol and CS pretreatment. Mechanistically, probucol and CS decreased the expression of JNK protein and increased the expression of ERK protein. CS can effectively reduce kidney damage caused by contrast medium. The underlying mechanism may be that CS accelerates the recovery of renal function and renal pathology by reducing local renal oxidative stress and influencing MAPK signal pathways.