The present invention relates to a mosquito-killing illuminating lamp which comprises a casing and a control unit. The casing comprises an illuminating portion and a mosquito-killing portion. The illuminating portion is provided with illuminating components therein. An electrolysis carbon dioxide generating device and a fan are provided inside the mosquito-killing portion. The control unit controls operation of the illuminating components, the carbon dioxide generating device and the fan. The electrolysis carbon dioxide generating device comprises a box body and electrolysis components. The electrolysis components are provided inside the box body. An electrolyte solution is provided inside the box body. The box body is provided with a venting hole. The electrolysis components comprise a graphite electrode and a cathode plate. After conduction between the graphite electrode and the cathode plate, electrolysis is performed on the electrolyte solution to generate carbon dioxide.