With the rapid development of cable TV, the use of optical fiber is more extensive. However, the laying of optical cables is often restricted by the environment such as traffic and spot layout, and the number of connections between optical cables is increasing. The failure of cable television transmission due to poor connection quality occurs from time to time. Most of these faults are caused by optical fibers. The selection and use of fiber optic splice closures are caused by improper use. Therefore, the reasonable selection and use of field fiber optic splice closure is an important part of improving the reliability of optical fiber transmission. Choosing the right fiber optic splice closure first the capacity of the fiber tray should be considered. The cable network fiber transmission mainly uses the star network structure from the front room to the light receiving points. The number of optical fibers in the optical cable is often more or less, and the optical fiber cable connection is continued. The number of optical cables and the number of optical fibers are not the same. Therefore, the capacity of the optical fiber tray must be properly selected. If the capacity is too small, the optical fibers will be difficult, and if the capacity is too large, it will cause waste. The fiber optic splice closure should have good airtightness to improve the tensile strength of the optical fiber. Apply 1-2 layers of pre-coating during production to make the tensile strength reach about 7kg. If the fiber optic splice closure is wet, Gas and water will accelerate the aging of the optical fiber surface coating, and will also cause the existing micro-crack on the surface of the optical fiber to expand. Over time, the strength of the optical fiber will be greatly reduced, and the service life of the optical fiber will be shortened. Fiber Closure should be easy to maintain and reuse. Due to the continuous development of urban construction, more cable TV trunk lines are being rerouted, and some residential communities are under construction. The number of optical fiber cores must have a certain amount of reservation so that it can be extended to the future. Newly built cells, therefore, the selection of fiber optic splice closures must take into account the convenience of reconnecting and reconnecting the fibers.