To evaluate the environmental quality of different poultry houses, the concentrations and compositions of microbial aerosols and PM2.5 were measured. Results showed that the concentrations of airborne bacteria, airborne fungi and airborne Escherichia coli in poultry houses were 0.167-4.484 × 104 CFU/m3, 0.236-4.735 × 103 CFU/m3, and 0-33.0 CFU/m3, respectively. Distributions of bacteria and fungi at levels 5 and 6 of the Andersen sampler were 11.4%-34.3% and 16.8%-37.5%, respectively. Conditional pathogenic bacteria including Klebsiella pneumoniae, Staphylococcus epidermidis, Enterococcus and Aerococcus viridans, were detected at the aforementioned level, in particle sizes similar to PM2.5 and with PM2.5 concentrations in poultry houses of 114-230 μg/m3 . In PM2.5, the chief bacteria genera were Faecalibacterium, Bacteroides, and Escherichia, whereas the dominant genus of fungus was Aspergillus. Importantly, the relative abundances of Escherichia and Corynebacterium in broiler houses were 3.1% and 1.94%, respectively, which were greater than those in layer houses. However, the percentages of Aspergillus and Penicillium were 13.5% and 0.56%, with a relatively high level in layer houses . Altogether, results revealed that the ambient air quality in poultry houses had a relatively high abundance of conditional pathogenic bacteria and concentration of PM2.5, which could threaten the health of animals and workers.