Primary membranous nephropathy (PMN) is a leading cause of nephrotic syndrome in adults. The discovery of antibodies against phospholipase A2 receptor (PLA2R) has ushered in the era of biomarker-based diagnosis and therapeutic monitoring for PMN. The cornerstone of immunosuppressive therapy lies in risk stratification based on proteinuria levels, renal function, and dynamic changes in anti-PLA2R antibody titers, enabling individualized timing of treatment initiation with the dual goals of achieving both immunological and clinical remission. This article systematically reviews the initiation timing, first-line therapeutic options—including cyclophosphamide combined with corticosteroids, calcineurin inhibitors, and anti-CD20 monoclonal antibodies—and key considerations for follow-up and relapse management in PMN, integrating evidence-based findings with clinical practice to inform individualized decision-making.