Complex localized pain syndrome (CRPS) refers to a clinical syndrome characterized by severe intractable, variable pain, malnutrition, and dysfunction secondary to accidental injury, medical injury, or systemic disease. It includes two typical types of sympathetic pain disorders, namely reflex sympathetic dystrophy and burning neuralgia. Clinical features of CRPS 1, pain: most patients are induced by mechanical, warm, mental and emotional stimuli, and such pain includes spontaneous pain, nociceptive hypersensitivity and nociceptive allergy and other neurogenic pain. In some cases, 3 to 6 months or even longer after the injury, there can still be persistent pain, and spread to the surrounding area. 2.Nutritional disorder: in the injury site and its surrounding tissues, often accompanied by vasomotor nerve dysfunction, swelling. Sometimes, although the edema is not obvious, it often complains of swelling. The skin begins to sweat, mostly in the form of wetness and flushing. Skin temperature may be high or low and variable, with a tendency for the skin temperature to decrease in the later stages, showing ischemic changes. With the progressive development of the disease, the growth rate of hair and nails changes from accelerated to slowed down, and skin thinning, nail curling and loss of luster gradually appear. 3.Motor function: Grip strength and fine motor function can be reduced in the early stage. As the range of motion decreases, the joints become stiff due to muscle wasting atrophy. Patients often in the course of 6 months later, due to subcutaneous tissue atrophy, skin thinning bright, affected skin sweating increased or decreased. If myofascial hypertrophy is present, it may lead to joint contracture and osteoporosis, which can be seen on X-ray. Diagnostic criteria for CRPS ① Long or recent history of injury or disease. ② Persistent burning pain with neurogenic pain manifestation. ③ There is vascular and sweating dysfunction, trophic changes such as muscle atrophy, limb edema or dehydration, and hypersensitivity to cold and other stimuli. ④ Diagnostic sympathetic nerve block test is mostly positive. Once diagnosed, CRPS treatment should seek ways to reduce pain as early as possible, while actively carrying out rehabilitation. 1.Preventive treatment: Perfect treatment of trauma and adequate analgesia in the early stage of injury are very important. That is to say, perfect control of pain in the acute stage, to prevent it from developing in the direction of chronicity, and at the same time, combined with the treatment of mental aspects, it is generally believed that a better therapeutic effect can be achieved. 2, transcutaneous electrical stimulation (TENS): transcutaneous electrical stimulation is through the activation of endogenous opioid peptide and analgesia, but also can stimulate the pain site of the thick fiber nerve, change the sensory impulses into the central nervous system, to achieve the purpose of reducing pain. 3, drug therapy: ① antidepressants: commonly used amitriptyline, promethazine, doxepin, mepitriptyline and other three (four) cyclic antidepressants. ② Anti-spasmodic drugs: representative drugs are carbamazepine, phenytoin sodium, sodium valproate, which is effective for nerve shock-like pain. The more widely used abroad is gabapentin, which can significantly relieve neuralgia caused by diabetes or herpes zoster. ③ Non-steroidal anti-inflammatory analgesic drugs: Neurotropin, prostaglandin preparations, hormones, morphine-like drugs. 4.Neuroblock treatment: sympathetic nerve block is the main. Commonly used nerve block: SGB, thoracic sympathetic nerve block, lumbar sympathetic nerve block, intraventricular local nerve block, epidural block, subarachnoid space block. The sympathetic nerve block performed in the clinic mainly plays a role by blocking the pain mediated by it and dilating the blood vessels in the area of its innervation. 5.When there is no improvement or only temporary improvement of pain symptoms after anesthetic block, the use of nerve-destroying drugs, nerve destruction or sympathectomy should be considered. 6.When the above treatments are ineffective, the implantation of analgesic pacemaker or subarachnoid analgesic pump can be considered. 7.Psychological treatment.