Abstract: A lamp seat of double layer structure for X'mas lamp string, includes an inner film layer made of soft and elastic material, which envelops a bulb seat and related elements, being of a T shape, having a top transverse pipe with its pipe body having a reduced diameter, and having a vertical pipe body silghtly enlarged, an inner protruding annulet provided in the bottom outer pipe portion thereof snugly pressing against the body of the bulb; an outer cover layer is laid over the outer peripheries of the concaved pipe body of the top transverse pipe and the vertical pipe body, and let the side pipe portions and bottom outer pipe portion be exposed; therefore, the conductor and the pipes and the bulb can be assembled in tight connection relationship to improve the water proofing effect.