An LED bulb structure having an insertion end includes a first electrically conducting pin, a second electrically conducting pin having a die pad at an end thereof, and an LED unit electrically connected to the first electrically conducting pin and the second electrically conducting pin through a first leading wire and a second leading wire, respectively, and a cap enclosing the above-mentioned components and leaving part of the first electrically conducting pin and the second electrically conducting pin exposed thereoutside. The first and second electrically conducting pins are adapted to form bayonet connections. An LED bulb structure having a heat dissipation element has the heat dissipation element attached to the pin portions of the electrically conducting pins. An LED bulb structure having a heat-and-electricity separated element further has a thermally conducting pin.