Abstract: A mosquitocidal light bulb having a seat and lighting elements; the seat is connected with a mouth of a light bulb; the seat is provided with a connecting seat; a circuit board electrically connected with the seat is provided inside the connecting seat; the circuit board includes a lighting control circuit board and a mosquito killing control circuit board; the light elements are connected to the connecting seat and electrically connected with the lighting control circuit board; a mosquitocidal device is connected with the connecting seat and electrically connected with the mosquito killing control circuit board. The mosquitocidal light bulb provided can replace an existing ordinary light bulb and uses existing wire arrangements. Therefore, it is not necessary to change the existing wire arrangements and switch controls to provide both mosquito killing function and lighting function.