In August,1937, Peking was occupied by Japanese intruders. At that time, Lin was an associate professor. She had become acquainted with a special patient, Bingxin (the pen name of Xie Wanying), the famous writer. Bingxin was impressed by Lin's ability to think and act quickly. They became good friends. Later, in one of her articles, Bingxin wrote: "With nimble hands, Lin helped give birth to thousands of babies; she not only helped the babies see the world, but she also guided their parents on how to nourish their children with limited food supplies. She helped nurture numerous fighters of the nation!"

In September 1939, Lin received a grant from her hospital and she went to the United States to study. In the obstetrics and gynecology laboratory affiliated with the Medical School of Chicago University, Lin continued her research into the relationship between contractions of the womb and the breathing of the fetus. Due to her outstanding achievements, her photo was displayed in the corridors of the teaching building, which was an honor. The following year, she was named an honorary member of the Chicago Academy of Nature. Lin gave up an opportunity to stay in America, and she returned to war-torn China in the winter of 1940.

On January 20, 1951, the new government of the People's Republic of China took control of Union Medical University. Lin began to worry about the development and normal operations of the hospital. The ideology and movements of reform ushered in by the new government tended to confuse Lin. She read the Bible for spiritual strength.

In March 1953, Lin attended the Beijing Women's Congress, and she was elected vice-chairwoman of the Municipal Women's Federation. In April, she attended the Second National Women's Congress, and she was elected a member of the executive committee of the China Democratic Women's Federation. In May, she attended a world medical conference, in Vienna, as a member of China's delegation.

In the following year, she was elected a representative of the first National People's Congress. During the following national congresses, she delivered speeches on how the government could ensure health care in factories, to prevent occupational diseases, improve the quality of medical workers and to conduct medical research.