Quinolones are a relatively new class of synthetic antimicrobials. These drugs have a broad antimicrobial spectrum, strong antimicrobial capacity, good oral absorption, higher tissue concentrations, no cross-resistance with other antimicrobial drugs, and fewer adverse reactions. Quinolones are divided into one, two, three and four generations. The first generation of quinolones is less used nowadays, because its antibacterial spectrum is narrower, its antibacterial ability is weaker, and it is only active against most of the gram-negative cocci, so it has been eliminated. The second-generation quinolones, mainly cinoxacin, are effective against Pseudomonas aeruginosa and have improved antibacterial activity, but the blood concentration is low, and they are only suitable for intestinal and urinary tract infections, and they are also less frequently used at present. The most used is the third generation of quinolone drugs, there are ofloxacin, levofloxacin, ciprofloxacin, long half-life, antibacterial spectrum can be expanded to gram-positive cocci, on mycoplasma, chlamydia, legionella, also has obvious effect. The fourth generation is the quinolones represented by moxifloxacin, with a long half-life, wide distribution in the body, high antibacterial activity, and a comprehensive efficacy that has exceeded that of the β-lactam antibiotics.