Abstract: A LED bulb for replacing a halogen bulb in the form of reflective cup comprises a housing (1), a collective lens (2), a LED circuit board (3), a number of LED chips (4) provided on the LED circuit board (3), a heat radiator (6) and a driver (7). The LED circuit board (3) is provided in the cavity (12) of the housing (1) and is connected to the heat radiator (6). The collective lens (2) is provided at the lower opening of the cavity (12). The housing (1), the heat radiator (6) and the driver (7) are connected in sequence from the bottom up. A circular ring (10) is provided on the outer wall of the lower end of the housing (1), and the circular ring (10) is detachably connected to the housing (1). The external diameter of the circular ring (10) is equal to the external diameter of the reflective cup (91) of the halogen bulb (9), and the height of the circular ring (10) is equal to the height of the annular flange of the reflective cup (91).