Objective: To evaluate renal damage after off-clamp partial nephrectomy (PN) using a novel surgical device, piezo actuator-driven pulsed water jet (ADPJ) system. Methods: Sprague-Dawley rats were divided into 4 groups and subjected to sham operation, off-clamp PN by the piezo ADPJ system, radio knife, and soft coagulation, which have been used as thermal coagulation devices. Urine and blood samples were collected, and residual kidneys were harvested at 1, 7, 14, 30, and 90 days after PN. Serum blood urea nitrogen, creatinine, and urinary and serum kidney injury molecule-1 KIM-1 levels were measured. Morphological features and the extent of renal ischemia of resection surfaces were evaluated by hematoxylin-eosin staining and immunostaining using antibodies to 1-methyladenosine, respectively. In addition, the expression levels of KIM-1 mRNA extracted from each resection surface were analyzed by quantitative real-time reverse transcription polymerase chain reaction. Results: Serum blood urea nitrogen and creatinine were significantly lower with the piezo ADPJ system than with soft coagulation. Urinary and serum KIM-1 levels were also significantly decreased with the ADPJ. The extent of 1-methyladenosine immunostaining was significantly less with the ADPJ than with thermal coagulation devices. The expression levels of KIM-1 mRNA were also lower in the ADPJ system group. Conclusion: The piezo ADPJ system might attenuate renal damage after off-clamp PN.