Objective: Urolithiasis is obstructive uropathy that can progress to acute pyelonephritis by retrograde urinary tract infection. This study aimed to assess the clinical features of acute pyelonephritis with urolithiasis based on the computed tomography (CT) findings. Methods: The medical records of patients who visited the emergency room were reviewed retrospectively from January 1, 2018, to January 31, 2021. This study investigated 109 patients (over 14 years old) diagnosed with acute pyelonephritis by kidney computed tomography. In the patient with acute pyelonephritis with urolithiasis, there were some findings like wedge-shaped hypodensity, kidney enlargement, perinephric fat stranding, pelvicalyceal wall thickness and enhancement, Gerota’s fascia thickness, and delayed excretion of contrast. The subjects were classified into two groups according to the number of CT findings: less than three CT findings group (group 1) and three or more CT findings group (group 2). Results: A higher incidence of hypotension, tachycardia, and sepsis was observed in group 2 than in group 1 (all P<0.05). Furthermore, the high sensitivity C-reactive protein level was also significantly higher than group 1. The number and location of urinary stones had no significant relationship with the CT findings. Conclusion The characteristics of acute pyelonephritis with urolithiasis differ for each group. A significant correlation was observed between the number of CT findings and the prevalence of sepsis. Predicting the patients’ clinical characteristics and the presence of sepsis will be helpful in treatment.