Karyotyping analysis is a classical cytogenetic method for the prenatal diagnosis of fetal chromosomal aberrations. In order to standardize fetal chromosomal karyotyping analysis and adapt to the development of medical genetics technology, the Committee for the Prevention and Control of Birth Defect, Chinese Association of Preventive Medicine has organized the formulation of this guideline. The content has covered general requirements and standards for the analysis of fetal chromosomal karyotypes, analysis of chromosomal mosaicisms, and methods for determining the resolution of G-banding, etc., with the purpose to serve the clinical practice.