The main difference between third-generation cephalosporin and second-generation cephalosporin lies in the different antibacterial spectrum and different indications. 1. Antibacterial spectrum: the second generation cephalosporin has antibacterial activity against gram-positive cocci; it has antibacterial activity against some gram-negative bacilli, such as Escherichia coli, Klebsiella spp., Salmonella spp., Shigella spp. and Haemophilus influenzae. Representative drugs: cefuroxime, cefotiam, cefaclor. The third generation of cephalosporin has strong antibacterial effect on gram-negative bacilli of Enterobacteriaceae, among which ceftazidime and cefoperazone also have strong antibacterial activity on Pseudomonas aeruginosa. 2. Indications: The second generation of cephalosporins is commonly used in the treatment of respiratory tract, biliary tract, intestinal urinary tract and soft tissue, bone and joint, obstetrics and gynecology infections caused by sensitive bacteria. The third generation cephalosporin is commonly used in sepsis, meningitis, pneumonia, osteomyelitis, pelvic inflammatory disease and other serious infections caused by gram-negative bacilli. Regardless of whether it is second-generation cephalosporin or third-generation cephalosporin, the choice of cephalosporin drug therapy should be based on drug sensitivity tests, and should be avoided in patients with a history of cephalosporin allergy.