In February 2022，an infectious disease with respiratory symptoms was detected in yaks in northwest Sichuan Province. In order to identify the etiology leading to the disease，an etiological diagnosis for related pathogens was carried out. A total of 20 lesions from 13 infected yaks were collected to detect 9 bovine respiratory pathogens including bovine viral diarrhea virus（BVDV），bovine parainfluenza virus type 3（BPIV-3），bovine infectious rhinotracheitis virus（IBRV），bovine coronavirus（BCoV），bovine respiratory syncytial virus（BRSV），bovine adenovirus type 3（BAdV-3），Pasteurellus multitolutoides（P. multocida，Pm），M. haemolytica（Mh）and M. bovis（Mb）by PCR. The results showed that IBRV，BAdV-3 and Pm，even co-infection，were detected from 20 samples，but no other pathogens were observed；the following viruses were detected：IBRV from 3 and BAdV-3 from 1 out of 4 whole blood samples；IBRV from 1 placental tissue sample and 3 out of 8 nasal swab samples，BAdV-3 from 5 nasal swab samples and 2 abortion swabs，and Pm from 4 out of 5 lung tissue samples；it was determined that，through further typing and identification of IBRV and Pm，the yaks were infected with IBRV 1.2 type and Pm A type. In conclusion，the respiratory disease prevalent in the region was caused by IBRV 1.2 type，BAdV-3 and Pm A type. It was confirmed by the study that BAdV-3 and IBRV 1.2 type were available and prevalent in yaks in the region，providing a reference for the prevention and control of respiratory diseases in local yaks.