Jin Guangying, 77, of Shuyang town, Jiangsu province, went to to Shuyang Leniency Hospital for an x-ray.
"We were surprised to learn there was a bullet inside her head," her son, Wang Zhengbang, told the Yangtse Evening Post.
Jin remembers that she was shot in 1943 during the Second World War by the invading Japanese army when she was taking supplies to her guerrilla father.
"I was 13, living along the railways in Xuzhou city. One afternoon in September, my mother asked me to take a meal to my father and his colleagues who were fighting the Japanese," she said.
"I was spotted by the Japanese army. They ran after me and opened fire. A bullet passed through the corner of my right ear. I hit the ground and lost consciousness."
When Jin regained consciousness, she was already back home in bed. Her mother applied herbal medicines to the wound. Amazingly, she recovered after three months.
Jin later learned that the bullet had gone through the arm of a person beside her before hitting her head.
The chief surgeon, who removed the rusty bullet, was amazed it had remained in her head for so long without causing major problems.
"The fact that the bullet lost strength and speed passing through another person, and that the point it struck is not vital, may explain her survival," he said.