Sciatica is a clinical syndrome characterized by pain in the region of the sciatic nerve distribution. The vast majority of patients with sciatica are secondary to the stimulation and compression of the sciatic nerve by lesions of the local and surrounding structures of the sciatic nerve, called secondary sciatica; a few patients are caused by sciatica, called primary sciatica. The sciatic nerve is mainly distributed in the posterior thigh, posterior lateral calf and foot. Patients with severe pain may be in a characteristic posture; lumbar flexion, knee flexion, toe landing, etc. Some patients may have signs such as hypotonia; altered Achilles and knee tendon reflexes. Secondary sciatica accounts for the majority of patients with sciatica, among which sciatica caused by lumbar disc herniation is the most common, and is clinically characterized by weeks or months of low back pain, followed by sciatica in one lower limb. Of course, other diseases of the lumbosacral region, such as: lumbar spine osteoarthropathy, lumbosacral spine congenital malformation, sacroiliac arthritis, etc., also tend to cause sciatica. Sciatica is rare clinically and is often accompanied by various types of infections and systemic diseases, such as upper respiratory tract infections. The sciatic nerve is more superficial and is susceptible to sciatica when exposed to moisture or cold. Therefore, what we usually call sciatica is not a disease, but a clinical manifestation that occurs during the attack of other diseases. We need to correctly understand sciatica as a clinical syndrome, and once sciatica occurs, we need to go to the hospital to identify the cause and treat it accordingly to relieve the pain symptoms in order to improve the quality of life and regain a healthy life.