The invention discloses a method for extracting and recycling penicillin sulfoxide. The method comprises the following steps that a, a penicillin sulfoxide solution is subjected to impurity separation through resin absorption; b, a penicillin sulfoxide desorption solution is obtained through resin desorption; c, a penicillin sulfoxide crystallization solution is obtained through the mechanical application of dissolution penicillin sulfoxide to the penicillin sulfoxide desorption solution or concentration of the penicillin sulfoxide desorption solution; d, the pH of the crystallization solution is adjusted with acid for crystallization, and the penicillin sulfoxide is obtained through filtration, washing and drying. The method can be used for extracting and recycling the penicillin sulfoxide from the low concentration penicillin sulfoxide solution, and therefore the yield of the penicillin sulfoxide is increased, the production cost is reduced, and environmental pollution is reduced. The quality of subsequent products like 7ADCA, cefradine, cefalexin and cefadroxil prepared from the penicillin sulfoxide produced through the technology is improved. Pharmaceutical compositions formed by cefradine, cefalexin, cefadroxil and a medically acceptable carrier can be utilized for treating respiratory tract infection like acute tonsillitis, angina, tympanitis, nasosinusitis, bronchitis and pneumonia, urinary tract infection, skin soft-tissue infection and the like caused by sensitive bacteria.