The smart substation changes the construction mode of traditional substation, in which the optical fiber cable becomes the main medium for communication because of its network. The existing connecting way of outdoor optical fiber cable has many disadvantages and can not satisfy the need of smart substation development. A solution based on prefab optical fiber cable for the outdoor network is proposed, which had been successfully applied to practical project and could efficiently improve the security, reliability and stability of network communication in substation. This solution has many advantages, such as simple structure, convenient construction, safety, durable use. It can greatly shorten the construction period and improve the fault resistance ability of smart substation, with increasing a little investment.