Chlamydia trachomatis is a common pathogen of neonatal conjunctivitis. For the etiology of neonatal conjunctivitis, Chlamydia trachomatis ranks first, accounting for 10%-74%, much higher than gonococci, and can also lead to trachoma. Chlamydia trachomatis is a Gram-negative bacterium that lacks an enzyme system for synthesizing high-energy substances (e.g., ATP) and is a prokaryotic cell-type microorganism that parasitizes exclusively within epithelial cells. Chlamydia trachomatis is the closest pathogen of the genus Chlamydia to humans and is prone to invade the epithelium of the urinary and genital tracts. Chlamydia trachomatis is divided into 15 subtypes, with subtypes D to K causing genital tract and ocular infections; 10 serotypes, including D-K, Da, and Ia, cause neonatal conjunctivitis. Chlamydia trachomatis is widely present in the air, skin and secretions of patients, and it is transmitted through many different routes. In particular, people with trachoma often have red eyes and mucous discharge and sometimes runny eyes, and the trachoma pathogenic microorganisms contained in the secretions are easily spread to fingers, clothing, towels, washing utensils or other items they come in contact with, and when people are in close contact, Chlamydia trachomatis is easily spread through cross-contact. Therefore, repeated infections can be caused, thus increasing the severity of trachoma inflammation.