Some studies have demonstrated that vitamin D supplementation can improve the clinical symptoms of autoimmune diseases, but the exact effect of its use in the treatment of immune diseases is still unclear and further research is needed. Currently, the diseases that confirm the efficacy of vitamin D in relieving symptoms are multiple sclerosis, which can alleviate the progression of the disease; vitamin D can reduce kidney damage in patients with systemic lupus erythematosus; for inflammatory bowel disease, vitamin D can repair the intestinal mucosal barrier, maintain intestinal homeostasis, and improve the symptoms. Psoriasis application of vitamin D can produce more anti-inflammatory cytokines, suggesting that high-dose vitamin D can be used to treat psoriasis. Currently, it is recommended that patients with autoimmune diseases increase their vitamin D intake appropriately and increase light exposure, which can be beneficial in alleviating the condition. If the diagnosis of autoimmune disease is confirmed, it is recommended to go to the hospital in a timely manner, combined with the specific conditions, standardized treatment under the guidance of the doctor.