Insulation joints are usually installed in and out of station along natural gas pipelines in order to prevent the cathodic protection current of buried pipeline from abnormal loss. It will affect the operation of the main pipeline once the leakage of insulation joint connecting to it occurs. The main pipeline should be truncated and vented to be repaired if the leakage becomes worse. Based on the analysis of the insulation joint structure and leakage causes, different online repairing methods are proposed according to different working condition of leakage. In the case of minor leaks, the method of composite materials packaging can be adopted to repair pipeline on line. For the condition that leakage cannot be drained, fixture plugging can be used if condition is suitable for fixture installation by purging. Typical cases are analyzed and repairing method is verified for application, which will provide a theoretical guidance and technical support for leakage treatment of insulation joint along natural gas pipelines.