Objective To assess the effectiveness of statins in treating early diabetic kidney disease (DKD). Methods We searched the Cochrane Central Register of Controlled Trials (Issue 2, 2009), MEDLINE (1991 to August 2009), EMbase (1991 to August 2009), CBMdisc (1991 to August 2009) and CNKI (1994 to August 2009). We also handsearched relevant journals and conference proceedings. Randomized controlled trials (RCTs) in which statins were used to treat patients with early DKD were collected. Then we screened the retrieved studies according to predefined inclusion and exclusion criteria, evaluated the quality of the included studies, and performed meta-analyses by RevMan 4.2 software. Results A total of 281 articles were found and 22 articles inolving 1838 patients were finally included. All these articles were regarded as low quality. We chose the random-effect model to conduct meta-analysis because significant heterogeneities were found among these articles. The results of meta-analysis showed that after treatment with statins, there were significant reductions in urinary albumin excretion rate (UAER) (WMD= –55.77, 95%CI –74.20 to –37.34, Plt;0.000 01), serum creatinine (Scr) (WMD= –4.34, 95%CI –6.74 to –1.94, P=0.000 4), C reactive protein (CRP) (WMD= –1.48, 95%CI – 2.32 to – 0.63, P=0.006), total cholesterol (TC) (WMD= –1.33, 95%CI –1.75 to –0.91, Plt;0.000 01), and triglyceride (TG) (WMD= –0.72, 95%CI-1.17 to -0.27, P=0.002) in group treatment compared with group control. Funnel-plot displayed a symmetrical figure, indicating there was no publication bias. No severe adverse effects were found in these articles except 12 patients with high level of transaminase which were cured after using hepatic protect therapy. Conclusion Currently available evidence shows that with the reduction of TC and TG, statins may decrease UAER and Scr in patients with early DKD and the reduction of CRP may be involved in the mechanism. Statins provide effective renal protection and no severe adverse effects in treating early DKD. However, due to lack of quality in the included studies, more studies of better quality should be conducted