An LED light bulb includes a lamp shell, a light emitting assembly and a power receiving base. The lamp shell includes a light transmissive portion and a holding portion. The light emitting assembly includes a light source baseboard located in the light transmissive portion and a circuit board connecting to the light source baseboard. The circuit board is surrounded by a heat sink. The heat sink includes a heat collecting section and a holding section extended from the heat collecting section into the power receiving base such that the power receiving base fully encases the heat sink without exposing. The inner surface of the power receiving base connects to the outer surface of the holding section so that heat generated by the light source baseboard is absorbed by the heat collecting section and transmitted via the holding section to the power receiving base for dissipating.