The utility model provides an automatic disinfection device for a cell incubator. The automatic disinfection device comprises a disinfectant system, an ultraviolet lamp disinfection system and a control system, the disinfectant system comprises a disinfectant bottle, an input pipe, an ultrasonic atomizer, an air pump and an output pipe; the lower part of the disinfectant bottle is connected with an input port of an air pump through an input pipe; an output port of the air pump is connected with an input port of an output pipe; an output port of the output pipe is connected with a nozzle; an ultrasonic atomizer is arranged on the input pipe; the ultraviolet lamp disinfection system comprises a lamp holder and an ultraviolet lamp connected with the lamp holder; and the control system is usedfor controlling the on-off of the input pipe, the start-stop of the air pump, the start-stop of the ultrasonic atomizer and the on-off of the ultraviolet lamp. The disinfection device can automatically and regularly perform disinfection work, is convenient to operate, improves the disinfection effect while reducing manpower and material resources, and is mainly used for disinfection of equipmentsuch as cell incubators, biochemical incubators and the like.