Objective: To analyze the clinical and laboratory features of patients with acute tubulointerstitial nephritis (ATIN) and its differential diagnosis with acute tubular necrosis (ATN). Methods: From January 2009 to December 2018, patients with ATIN or ATN confirmed by renal biopsy in the Department of Nephrology, Ruijin Hospital ，Shanghai Jiao Tong Universtiy School of Medicine were included. The clinical manifestations and laboratory examination data were collected and analyzed comparatively. Results: During the period, there were 5 537 patients receiving renal biopsy,inclu-ding 135 ATIN cases [2.4% (135/5 537)] and 109 ATN [2.0%(109/5 537)].ATIN accounted for 21.4% (135/630) of the acute kidney disease (AKD) patients. The median age of ATIN patients was 53 years old and the female proportion was 57.0%. Main clinical manifestations of ATIN included fever, rash and arthralgia. Infection, and medicine use and toxic exposure were common inducements of ATIN. Compared with the ATN group, ATIN patients had higher female proportion (57.0% vs 33.9%) and lower BMI (22.9±3.6 vs 24.6±3.9, P<0.01). The occurrence of acute kidney injury (AKI) (14.8% vs 64.2%), oliguria（17.0% vs 48.6%）, and emergency dialysis after admission （19.3% vs 39.4%）in ATIN patients is lower (P<0.01). Hemoglobin (Hb) level [(100.9±20.9) g/L vs 116.7±29.8 g/L)] and blood urea nitrogen/creatinine ratio (BCR) (11.8±5.4 vs 14.6±11.0) in patients with ATIN were lower than those in ATN group(P<0.01). Multivariate regression analysis showed that high serum albumin（55 g/L）, low serum creatine (Scr) (<62 μmol/L), low uric acid (UA) (<208 μmol/L), and low Hb levels(<130 g/L) on admission were associated with ATIN. The predictive model combining the above four indicators showed that the area under the curve for diagnosing ATIN was 0.798 (95%CI: 0.742-0.853), with a sensitivity of 74.4% and a specificity of 71.4%. Conclusions: ATIN accounts for a high proportion in biopsy-confirmed AKD patients from Shanghai. It is more common in middle-aged women. Half of the patients have unknown causes, and their clinical manifestations are similar to ATN. Serum albumin, Scr, Hb, and UA levels at admission are helpful to the differential diagnosis of ATIN and AIN. The diagnostic prediction model based on the above four indicators showes good specificity and sensitivity.