In early January 1937, Smedley paid a visit to Yan'an upon the invitation of the Communist Party of China, during which she interviewed Mao Zedong, Zhu De, Zhou Enlai, Peng Dehuai and others. With the consent of Zhu De, Smedley started to make preparations for Zhu's biography----《The Great Road: The Life and Times of Chu Teh》. In Oct. 1937, Smedley arrived at the general headquarters of the Eighth Route Army located in the mountainous area in northern Shanxi, and became the first foreign military reporter of the Eighth Route Army. In January 1938, Smedley journeyed to Hankou, where she worked in the capacity of the reporter of the Manchester Guardian and a staff of the China Red Cross Society. Smedley reported on the situation of the War of Resistance Against Japanese Aggression in China, at the same time she helped rescue the wounded and refuges, and appealed to international organizations to provide assistance to China.

Smedley returned to The United States in May of 1941 due to her illness. In America, Semdley continued to make speeches and write articles to let the American people know the real situation of the War of Resistance Against Japanese Aggression in China, and she collected donations for Chinese people's war of anti-Japanese aggression. On May 6, 1950, Smedley died of acute circulatory failure in London at the age of 58. On the same day the following year, a memorial ceremony and a grand funeral were held in memory of her in Beijing. Her ashes were laid to rest at the Babaoshan Revolutionary Martyrs' Cemetery in Beijing. On her gravestone was engraved the golden inscription written by Zhu De: Buried here is Lady Smedley, an American Revolutionary Writer, and a Friend of the Chinese People.