Abstract：This paper introduces the clinical experience of Professor ZHOU Ping'an in treating fever due to internal damage. Professor ZHOU Ping'an believes that the basic pathogenesis of fever due to internal damage lies in the deficiency and weakness of healthy qi， on the basis of which qi， blood， yin， yang， constraint， dampness， stasis， etc.， so the treatment should be based on different causes to take the method of tonifying deficiency and draining excess， as well as sweat promotion method， heat- clearing and fire-draining method，and venting method. Meanwhile，defense qi should be guarded and protected， so as to achieve the purpose of "harmony". Thus，a good effect can be obtained.