Abstract: The operation environment of overhead transmission line is complex, and it needs to cross obstacles such as railway, highway and transmission channel. During the construction of crossing these obstacles, in order to prevent the accidental fall of transmission line and ground wire from causing injury to vehicles and pedestrians or causing short circuit grounding of the crossed transmission line, the line must be sealed, that is, the net rope or net pole shall be fixed above the crossed object to form a protective barrier to prevent accidents. The transmission line network sealing device is used to seal the network, which innovates the previous manual network sealing operation mode, breaks through the limitation of traditional operation environment, and effectively avoids the high fall and electric shock risk of operators.