To observe therapeutic effect of Danhong Injection on diabetic peripheral neuropathy (DPN) based on collateral disease theory.Methods:A total of 128 cases of DPN patients were randomly divided into two groups: the control group(42 cases) and the treatment group(86 cases).Two groups were both given hypoglycemic drugs and neurotrophic drugs. The treatment group was also treated with Danhong Injection.Results:The total effective rate of treatment group was 80.2%， while the total effective rate of control group was 69%. The curative effect of treatment group was better than the control group( P<0.05).Conclusion:With the guidance of collateral disease theory， Danhong injection has better clinical effect in treating DPN.