Abstract: The origins and behaviors of natural gas hydrates formed in pipeline are described and analyzed. Based on analytical results, a method to predict the formation zone of natural gas hydrates is given. Three precautionary measures to prevent natural gas hydrates in pipe from blocking are put forward, that is, not to used bending pipe if possible during construction stage; increasing pigging frequency before pipeline commissioning to elimninate water within pipe; injecting inhibitor in regular way. For the pipe section with natural gas hydrates formed, several effective methods to treat NGH are suggested to use, that is, depressurizing as fast as possible; heating the pipe; injecting methanol/ethylene glycol and venting.