Background: Henoch-Schönlein purpura nephritis (HSPN) is a common vasculitis involving the kidneys, with a lower incidence in adults. Meanwhile, nephrotic syndrome (NS) can appear in HSPN. However, the clinicopathological features and renal outcome of adult-onset HSPN presenting with NS (NS-HSPN) have not been well clarified. Methods: A total of 191 HSPN patients were prospectively analyzed and comparisons were made between NS-HSPN and non-NS-HSPN. Multivariate Cox regression analysis was carried out to find the unfavorable factors of renal outcome of NS-HSPN. Results: Among the 191 patients, 44 (23.0%) had NS-HSPN. Apart from edema and abdominal pain, patients with NS-HSPN tended to have lower levels of erythrocytes and hemoglobulin in blood as well as a greater number of erythrocytes in urine (p < 0.05). Mesangial proliferation was the most common pathological lesion in HSPN and the rates of crescent formation were significantly different, with 54.5% in NS-HSPN and 33.3% in non-NS-HSPN (p < 0.05). Notably, 18.2 and 4.8% of patients reached the composite endpoints in the NS-HSPN and non-NS-HSPN groups, respectively (p < 0.05), demonstrating that NS-HSPN patients were more likely to progress to end-stage renal disease and had a worse outcome. We also found that hypertension, estimated glomerular filtration rate (eGFR), cystatin, and tubular atrophy/interstitial fibrosis (HR > 1, p < 0.05) at onset were correlated with adverse outcome in NS-HSPN. Conclusion: NS-HSPN had more severe clinicopathological manifestations and poorer prognosis. The adverse predictors of NS-HSPN principally depend on clinicopathological presentation rather than on different therapies, and hypertension, eGFR, cystatin, and tubular atrophy/interstitial fibrosis can serve as independent risk factors in NS-HSPN.