Generalized pustular psoriasis (PPG) is a rare subtype variation of pustular psoriasis. No specific therapeutic agent for PPG has been approved in the United States and Europe yet. Standard guidelines for PPG therapy do not yet exist, so therapy is determined based on the clinical. A case is reported, a 22-year-old woman with complaints of purulent papules on almost the entire body for 1 week ago. The patient had a history of red scaly patches for 3 years ago. On generalized regional dermatological status, diffuse miliary pustules were found on an erythematous basis with desquamation. Histopathological results showed subcorneal pustules with segmented (spongiform) neutrophil inflammatory cells infiltration. The patient was diagnosed as PPG and treated with methotrexate 7.5 mg/week. The patient showed significant lesion improvement within 14 days of treatment.