An illuminated door sill plate for a car door threshold, comprising: a base including an elongated case and a waterproof plate connected with a bottom of the elongated case so as to form an accommodation space between the elongated case and the waterproof plate, a PCB accommodated in the accommodation space and having a light-emitting diode, and at least one changeable battery, wherein the elongated case has a light emitting portion arranged on the elongated case, a light guide plate arranged between the light emitting portion and the PCB, multiple engagement portions arranged on two long sides of the elongated case, at least one first receiving orifice defined proximate to one of the two short sides of a top of the elongated case and configured to receive the changeable battery, and at least one battery cover configured to cover the at least one first receiving orifice; and the illuminated door sill plate further comprises a removable cover including an elongated body extending in a longitudinal direction and connected with a nameplate, wherein the nameplate includes a light transmission portion formed on center of the nameplate in character shapes and configured to transmit lights, characterised in that the elongated body comprises an elongated groove formed on center of a top of the elongated body, and multiple hooks extending from two long sides of the elongated groove and engaged with the multiple engagement portions so that the base is removably connected with the removable cover; that the removable cover has two ends opposite to each other in the longitudinal direction, and each of the two ends of the removable cover accommodates a magnet so as to be attached on a car door threshold (B, the removable cover having a length longer than a length of the base; wherein when the removable cover is connected to the base, the two magnets are disposed outside the base; and that a bottom of the base has a double-sided tape for adhering the base to the car door threshold. a base including an elongated case and a waterproof plate connected with a bottom of the elongated case so as to form an accommodation space between the elongated case and the waterproof plate, a PCB accommodated in the accommodation space and having a light-emitting diode, and at least one changeable battery, wherein the elongated case has a light emitting portion arranged on the elongated case, a light guide plate arranged between the light emitting portion and the PCB, multiple engagement portions arranged on two long sides of the elongated case, at least one first receiving orifice defined proximate to one of the two short sides of a top of the elongated case and configured to receive the changeable battery, and at least one battery cover configured to cover the at least one first receiving orifice; and the illuminated door sill plate further comprises a removable cover including an elongated body extending in a longitudinal direction and connected with a nameplate, wherein the nameplate includes a light transmission portion formed on center of the nameplate in character shapes and configured to transmit lights, characterised in that the elongated body comprises an elongated groove formed on center of a top of the elongated body, and multiple hooks extending from two long sides of the elongated groove and engaged with the multiple engagement portions so that the base is removably connected with the removable cover; that the removable cover has two ends opposite to each other in the longitudinal direction, and each of the two ends of the removable cover accommodates a magnet so as to be attached on a car door threshold (B, the removable cover having a length longer than a length of the base; wherein when the removable cover is connected to the base, the two magnets are disposed outside the base; and that a bottom of the base has a double-sided tape for adhering the base to the car door threshold.