Trichomonas gallinae is a globally distributed protozoan parasite that causes avian trichomoniasis, leading to significant morbidity and mortality in birds. The present study aims to investigate the prevalence, genetic diversity, and phylogenetic relationship of T. gallinae in various bird species in Beijing. A total of 413 oropharyngeal swab samples were collected from domestic pigeons, wild pigeons, and other bird species. The overall prevalence of T. gallinae infection was 32.0% (132/413). The infection was detected in domestic pigeons, wild pigeons, and red-necked turtledoves, but not in other wild birds. Molecular analysis identified two predominant genotypes, A and B, with genotype A found in wild pigeons and genotype B found in domestic pigeons. The present study provides valuable insights on the prevalence and genetic diversity of T. gallinae in Beijing. This can be useful for understanding its pathogen distribution and host range, and the development of strategies for the prevention and control of avian trichomoniasis.