The conformation of the light socket for outdoor-usage light string is quite different from that for indoor-usage. The light socket for indoor-usage provides minimal protection against moisture, and thus can not be used outdoors. There is a known conventional water-proof light socket showing in FIG. 1, in which a base (11) has a protractile separation plate (12) extended thereof to separate the end of said base as two portions to isolate the power wires. Although this conformation of the light socket can protect the light string from moisture, formation of a mold for this conformation is rather difficult and thus increases the cost. Therefore, it is not practical to use such light socket for indoor-application. Furthermore, there is a need to develop a light socket for both indoor- and outdoor-usage in a lower cost.