This study designed a buried channel metal-oxide-semiconductor (BCMOS) image sensor experiment to address increased dark current caused by low-energy electron bombardment (300 eV to 1500 eV) on the alumina passivation layer. For a CMOS image sensor with a 10 nm alumina passivation layer, an increase in the dark current rate is obvious when the bombardment energy is greater than 600 eV. When the bombardment electron energy does not exceed 1.5 keV, the dark current has a maximum value of about 12000 e-/pixel/s. Finally, after electron bombardment, the dark current of the CMOS image sensor decreased exponentially when the sensor was placed in an electronic drying cabinet. The main reason for the above phenomenon is the increased defect states at the interface between alumina passivation layer and silicon caused by incident electrons.