The aim of this study was to understand the clinicopathological features and prognosis of idiopathic membranous nephropathy (IMN) in youth. A retrospective analysis of the clinicopathological features and prognoses of pathologically confirmed IMN in 21 patients aged 15-30 years was performed. IMN was mainly characterized as nephrotic syndrome (NS), with stage I as the main pathological stage, and associated with hyperplasia of the glomerular mesangial cells and ground substance. High-intensity immunofluorescence also showed multi-site deposition of a variety of immune complexes, and electron microscopy showed multi-site deposition of electron-condensing substances. In the present study, 4 patients received non-specific treatment. Among 17 NS patients, 12 patients exhibited a preference for glucocorticoid therapy, and of these patients, 7 were sensitive to therapy and 5 were resistant. In the 12 patients who received hormone treatment combined with immunosuppressants (including 5 patients who were treated with the combination from the initial start, 5 patients who were steroid resistant, and 2 patients who were sensitive to the initial hormone treatment but who later showed relapse), complete remission was achieved in 6 patients, partial remission was achieved in 2, the treatment was ineffective in 2, and 2 patients were lost to follow-up. In conclusion, the clinical manifestation of IMN in youth in this study was mainly NS. In most patients, the initial hormone treatment was effective, and in some patients, the combination of hormone and immunosuppressant treatment was effective. As the sample size in this study was small, further clinical validation is still required to determine the efficacy of the treatment.