The accumulation of fluid in the uterine cavity,known as endometrial cavity fluid(ECF),is easy to be ignored in clinic due to its inconspicuous symptoms and the requirement of ultrasound for diagnosis.Its associa-tion with various female reproductive system disorders can significantly impact the physical and mental well-be-ing of women during their reproductive years.Presently,there is limited understanding regarding ECF,and eluci-dating its origins and associated mechanisms remains a formidable task.This article endeavors to offer a thor-ough and systematic examination of potential sources and mechanisms underlying ECF,aiming to furnish valu-able insights for clinical diagnosis,treatment,and scientific inquiry.