Abstract: Objective To investigate the early diagnosis and treatment for burn complicated with severe paroxysmal sympathetic hyperactivity (PSH). Methods Medical records of patients with burn complicated with severe PSH, admitted to our department from April 2016 to March 2019 and meeting the inclusion criteria were analyzed retrospectively. There were 4 males and 1 female, aged 17 months to 39 years, with an average of (21±16) years. During occurrence of PSH, the vital signs of patients were routinely monitored and oxygen were given. Other treatment included central venous catheterization and infusion of electrolyte solution, infusion of plasma according to patients′ condition, use of opioid analgesics and benzodiazepine sedatives, physical cooling and drug cooling, and establishment or maintenance of artificial airway and use of ventilator. Heart rate was controlled below 120 beats per minute in adults and 140 beats per minute in children with comprehensive treatment dominated by analgesia and sedation. Besides, single or multiple vasoactive agents, even in large doses were used to maintain normal blood pressure of patients. The occurrence characteristics, time, and treatment outcome of PSH were analyzed. Results PSH happened rapidly, with a sharp increase in several minutes to dozens of minutes. Five patients were with symptoms such as high body temperature, shortness of breath, very fast heart rate, normal or elevated systolic blood pressure, hyperhidrosis, and dystonia at the onset. The symptoms occurred simultaneously or successively. According to the Clinical Feature Scale, the above-mentioned 6 indexes achieved the highest score of 3 points except of systolic blood pressure. Four patients showed dilated pupils and impaired consciousness. Among the patients, PSH occurred in the acute exudation stage in 3 patients, in the fluid reabsorption stage in 1 patient, and in the late repair stage in 1 patient. PSH of patients lasted for 3 hours to 12 days. The symptoms of 4 patients were effectively controlled, and 1 patient died of deterioration. No PSH occurred in the cured patients during follow-up of 3 to 14 months. Conclusions Burn complicated with PSH can occur at any time before wound repair and in patients with different injury conditions. The causes of PSH include sudden burn, persistent pain, fright and fear, strange environment, low blood volume, and other adverse stimuli, and PSH is more likely to occur in children with underdeveloped brain function. Intravenous infusion of analgesics sedatives, physical therapy and medication to lower body temperature, stabilizing blood pressure and respiration are effective measures to treat PSH. PSH should be distinguished from the common complications of burns, such as sepsis, cerebral edema, hyperpyretic convulsion, transfusion response, stress disorder, etc.