Abstract： To introduce the clinical experience of Prof. MA Yunzhi in treating myasthenia gravis. Prof. MA believes that the basic pathogenesis of myasthenia gravis is the deficiency and injury of the spleen and stomach. He believes that the attention should be given to supplementing and boosting the spleen and stomach，and improving the splenic transportation and ascent of the clear in clinical practice. Besides，in Prof. MA's idea of "treatment based on the nature of zang- fu organs"， he puts forwards that the prescriptions and medication should be flexibly changed according to the relationship between the location， physiological characteristics，properties of the interior or exterior and yin or yang of zang-fu organs and the four properties，five flavours and channel entry，as well as the climate environment.