Kallmann syndrome is a rare genetic disease with genetic heterogeneity and phenotypic heterogeneity, and is one of the common types of congenital hypogonadotropic hypogonadism.The incidence rate of male is higher than that of female.The pathogenesis is associated with abnormal development and migration of gonadotropin-releasing hormone(GnRH)neurons during embryonic period.The main clinical features are hypogonadism and anosmia or hyposmia.It is difficult to make early diagnosis before puberty, and hormone detection in mini puberty is a window of opportunity for early diagnosis, and non-reproductive performance and gene detection are conducive to early detection of the disease.This article reviews the literature and summarizes the progress in etiology, diagnosis and early diagnosis, reversal and relapse, and treatment of Kallmann syndrome.