A bulb simulating light emitting diode headlight is disposed through a lamp bowl of an illumination device on a vehicle or motorbike body. The bulb simulating light emitting diode headlight includes a main body, a circuit board, and two light emitting diode modules. The main body has a seat, and a first plate and a second plate disposed on the seat. The first and second plates have a first opening and a second opening, respectively, and form a housing space. The circuit board is disposed between the first and second plates. The light emitting diode modules are disposed on two lateral sides of the circuit board and face the first and second openings. When the light emitting diode modules are broken, the user simply picks out the circuit for replacement, without the need of replacing all the components, thus lowering the cost.