Metachromatic leukodystrophy （MLD） is an autosomal recessive genetic disorder characterized by progressive aggravation of motor， sensory， and cognitive impairments， with high disability and mortality rates， and there are currently no effective treatment methods for MLD. Therefore， carrier screening among couples in pre-pregnancy and early pregnancy is crucial in reducing the birth rate of affected children. The clinical practice guidelines aim to identify the individuals at a high risk of carrying MLD mutation， offer early genetic counseling to reduce reproductive risks， and promote standardized prevention and control of MLD.