Pneumothorax is a very rare complication of ventriculoperitoneal shunting in children. We report a case of an iatrogenic bilateral tension pneumothorax during the placement of a subdural-peritoneal shunting. After the placement of peritoneal catheter, oxygen saturation of the patient quickly decreased, hypotension and bradycardia occurred. Intraoperative x-rays showed the pneumothorax. A thoracostomy tube was inserted and attached to an underwater seal. Vital signs improved in a short time period. The radiological improvement had been achieved in four days. Early diagnosis and prompt intervention are life-saving for this complication. To avoid this complication, the tip of the shunt tunneler should be always palpable during the placement of the peritoneal catheter, especially in children's shunt surgery.