Abstract: A 2-year-old male British blue shorthair cat, weighting 2.74 kg, had a long-term history of raw meat feeding, and had gradually lost weight in the past three months. Afterwards, the weight had dropped severely, and the symptoms such as anorexia and body yellowing had appeared. It had sudden difficulty breathing, bloody diarrhea, bloody stool, stench smell on the day of consultation. The body temperature increased and mental state was poor. In order to diagnose and treat the case, the test used blood routine, blood biochemical index, blood smear examination, PCR examination, stool examination, feline panleukopeniavirus（FPV） test panel, feline immunodeficiency virus（FIV） and feline leukemia virus（FeLV）,ascites analysis and B-mode ultrasound method for examination; clinical symptoms and examination results were integrated for diagnosis and treatment. The results showed that it was a mixed infection of feline Coronavirus and Mycoplasma haemofelis. Through the antiviral treatment for feline infectious peritonitis with the drugs GC376 and GS441524,and the targeted treatment for Mycoplasma haemofelis with doxycycline, five weeks later, the spirit and appetite had all recovered well. The results suggested that GC376,GS441524 and doxycycline had a good therapeutic effect on feline Coronavirus and Mycoplasma haemofelis mixed infection.