Objectives The causes of unknown mortality in a goat farm were identified to provide reference for the diagnosis and the control and prevention of similar diseases in goat farms. Methods A goat farm in Hubei Province reported an unexplained death of a goat in October 2023. The clinical symptoms of the affected goats mainly included an increase in body temperature to 41 ℃, diarrhea, runny nose, cough, etc. Authors conducted sampling for investigation and laboratory testing to identify the cause of the disease. On-site investigation was conducted and two deceased lambs with typical symptoms were subjected to necropsy. 20 blood sera, 20 nasal swabs, 6 samples of the ground environment in the sheep shed, and 2 lung tissue samples were collected from diseased goats for laboratory testing of antibodies against brucellosis, Peste des Petits Ruminants (PPR) pathogen, foot-and-mouth disease (FMD) pathogen, caprine contagious pleuropneumonia (CPP) pathogen, and parasitosis. Results Typical pathological features of contagious pleuropneumonia were found during necropsy. The results of laboratory testing showed that the antibodies against brucellosis, PPR pathogen, and FMD pathogen were all negative. One lung tissue sample was detected as positive for CPP. The results of microscopic examination showed that there were a large number of parasites and eggs of worms in 6 fecal samples. Conclusions The comprehensive diagnosis confirmed that there was the infection of parasitosis and secondary infection of contagious pleuropneumonia in goats from this goat farm.