By using indirecthemagglutination assay(IHA),100 serum samples from 7 areas yak farms of Huzhu county were tested for antibody against Toxoplasma gondi.i.The results were as follow:Average infection rate of 12.15 tested sera antibody titers were≥1:64 which was regarded as positive.Simultaneously,infection rate which yak were different sexes had no significant difference showed that infection rate had no reference to sexes.