Early-onset myasthenia gravis(EOMG)and early-onset Parkinson's disease(EOPD)are rare diseases,and few studies have been reported on these diseases.The paper reported the diagnosis progress of a case of EOMG combined with EOPD,then introduced the diagnostic criteria,clinical features and pathogenesis of the two diseases,intending to enhance clinicians'understanding of the two diseases and improve the diagnostic correctness of the combination of the two diseases.