Martha Root (1872-1939) was an exceptional religious and spiritual activist, a leading figure in the international women's peace movement, and a new organism of a new world in the early twentieth century. This thesis represents Martha Root from three aspects: the early life of Martha Root, her four world teaching trips from 1919 to 1939, with a focus on her peace advocacy, and an investigation into her gender awareness and identity construction by reflecting on Tahirih the Pure, Iran's Greatest Woman, Martha Root's only book.