Opto-electronic countermeasure is an important part of electronic countermeasure. Its position in modern war is becoming higher and higher. First, the opto-electronic countermeasure system is analyzed in both the opposite of opto-electronic reconnaissance and anti-reconnaissance and the opposite of opto-electronic jamming and anti-jamming. Then, the typical opto-electronic equipment and their application in the war are presented. Finally, the development trend of opto-electronic technology and equipment is summarized.