The invention belongs to the novel technical field of medicaments, and relates to a novel dosage form of amoxicillin used for treating: 1, upper respiratory tract infections, such as tympanitis, nasosinusitis, pharyngitis and tonsillitis resulted from streptococcus hemolyticus, streptococcus pneumoniae, staphylococcus or haemophilus influenzae; 2, genitourinary tract infections resulted from escherichia coli,proteus mirabilis or enterococcus faecalis; 3, skin and soft tissue infection resulted from streptococcus hemolyticus, staphylococcus bacteria or escherichia coli; 4, lower respiratory tract infections, such as acute bronchitis and pneumonia, resulted from streptococcus hemolyticus, streptococcus pneumoniae, staphylococcus bacteria or haemophilus influenzae; 5, acute simple gonorrhea; and 6, typhoid, typhoid bacteria-carrier, leptospirosis and the like. The novel dosage form is characterized in that the stomach floating tablet is hydrated into gel on the surface to expand the volume thereof after contacting with the gastric juice at the body temperature because of a plurality of hydrophilic macromolecular materials contained. Meanwhile, the weight of the tablet is less than the buoyant force of the gastric juice to float the tablet on the gastric juice and prolong the retention time in the stomach.