An LED lamp includes a lamp cover consisting of a plurality of sector-shaped connecting bodies, a plurality of fins attached to the lamp cover and a plurality of LED modules attached to the lamp cover and opposing the fins. A locking device is pivotably mounted to the lamp cover and comprises a supporting pole extending in the lamp cover, a plurality of branches pivotably mounted to the lamp cover and the supporting pole. The branches are movable along the supporting pole to be locked at a desired position, whereby an illumination angle of the LED modules of the lamp cover relative to the supporting pole is changeable via movement of the branches along the supporting pole of the locking device. Thus, an illumination area and an illumination intensity of the LED lamp are adjustable.