The best time for preconception screening is 6 months before conception to help understand the health status of both parents preparing for pregnancy, prevent miscarriage and reduce the risk of fetal malformation. General preconception tests include routine blood, urine, four coagulation tests, full biochemistry, thyroid function, diabetes screening, iodine, ferritin, vitamin D, lipids, hepatitis series, syphilis and HIV screening. In addition, men need to check semen routine and women need to have gynecological examination. If problems are found during the preconception checkups, they need to be promptly regulated and folic acid should be started 3 months before conception. Therefore, a checkup 6 months before conception can give both parents enough time to take care of their health. A good preconception checkup is good for eugenics and both parents should stop smoking and drinking during the preparation period and exercise properly to ensure the quality of sperm and eggs, which is good for the health of the fetus.