A LED lamp which could directly replace an ordinary tungsten, halogen, or electricity-saving light bulb, includes a LED filament, a lamp base, a thermally conductive electric insulator, and a mask. The thermally conductive electric insulator is filled in a cavity of the lamp base, and includes a first portion mechanically contacting the LED filament and an electrode of the lamp base to provide a first thermal channel from the LED filament to the lamp base, and a second portion adhering the mask to the lamp base to provide a second thermal channel from the lamp base to the mask. By using the mask to enlarge the heat dissipation area, a better heat dissipation effect is achieved.