Pulmonary alveolar proteinosis (PAP) is characterized by intra-alveolar accumulation of lipoproteinaceous material. The severe chronic pulmonary disease and susceptibility to pulmonary infection is a prominent feature of the disease. We reported a case of postnatal-onset PAP and chronic interstitial pneumonitis in a girl with chronic respiratory distress since she was 5 months of age. A lung biopsy confirmed the diagnosis. The therapeutic bronchoalveolar lavages, a short trial of granulocyte colony-stimulation factor (G-CSF) and a combination of low dose methylprednisolone and hydroxychloroquine were used at different times without noting satisfactory improvement. Intravenous immunoglobulin (IVIG) and pulse methylprednisolone were given monthly with gradual recovery. She did not require oxygen supplement after 21 months of this combination. Our report suggested that IVIG and pulse methylprednisolone might have a potential role in the treatment of PAP with chronic interstitial pneumonitis.