Experimental research on pulsed nanosecond laser irradiation on Charged Coupled Devie was carried out to understand the damage and blindness mechanism of multiple pulses interaction with EO systems. The results showed two distinctive damage effects and mechanisms. It exhibited damage and blindness accumulation effects and damage threshold reducing outcomes with multiple pulses arriving at the same spot on CCD, including point-to-line damage and line-to-full frame blindness. The threshold reducing outcomes is closely related with pulse number and laser fluence with the same mechanism as single short blindness. However, the damage mechanism for multiple-pulse damage to different pixels is obviously different, which attributes to a multiple vertical line damage superposed effect without electrical disorder. The functional blindness threshold is indentified with line damage threshold 660 mJ/cm2, and evidently less than that of single-pulse blindness threshold 1 500-2 200 mJ/cm2.(GKCP2016004)