The purpose of hallucinations is to replace real signals with simulated sensory signals that drive the autonomic nerves to perform psychosomatic actions. The patient has a dreamlike sensation, as if in a dream, often in conjunction with hallucinations, which are proven to be illusory by objective tests due to the lack of corresponding realistic stimuli, but are not illusory in terms of the patient’s own experience. Some patients are convinced that their perceptions come from objective reality. The following are the main diseases that can trigger hallucinations: 1, high fever: fever is a form of reaction to harmful stimuli, a certain degree of fever can awaken the body’s resistance, improve their own resistance to disease, is beneficial to the recovery of the disease, the human body has a fever situation indicates that the body has resistance and responsiveness to external harmful stimuli. 2, epilepsy: commonly known as sheep epilepsy epilepsy, epileptic seizures brain excitability of neurons suddenly, excessive repetitive discharge, resulting in sudden, temporary disorders of brain function, clinical manifestations of transient sensory impairment, limb convulsions, loss of consciousness, behavioral disorders or abnormalities of vegetative nerve function. 3.Deep temporal lobe tumor: Glioma is common, accounting for 17.96% of all intracranial gliomas, followed by meningioma, accounting for 5.42% of all intracranial meningiomas, and other metastases often occur in this area. It is common in adults, and there is no significant gender difference. In some states, including dreaming, the fantasy is separated from the self and the person does not perceive that he or she is fantasizing. Fantasies” are hallucinations in which information is taken from sensory memory and pieced together and sent back to the sensory area.