Abstract: The majority of medicines taken by children are unlicensed for children and off-label, with a lack of information regarding absorption, distribution, metabolism, bioavailability, safety, etc.. Pediatric medications are quite different from those for adults because of their unique characteristics of physiological development and pharmacokinetic behaviors. Children of different ages have their own safety threshold because of continuous maturation process; besides, children have their distinctive routes and requirements of administration during medication. Development of pediatric medicines with suitable formulations is a great challenge for pharmaceutical scientists. This paper briefly analyzes children's physiological development characteristics and their influence on the pharmacokinetic profile, and summarizes the methods of designing suitable dosage forms and the formulation principles for pediatric medicines.