Abstract: [Objective] To evaluate the prevalence of Toxoplasma gondii infection in grazing cattle and sheep in partial area of Inner Mongolia.[Method] A total of 286 serum samples were recovered from grazing cattle and sheep in Alagxa League and Hulun Buir, and the presence of the serous antibody against Toxoplasma gondii were detected by using indirect hemagglutination assay (IHA).[Result] The total positive rate of Toxoplasma gondii antibody in sheep serum samples collected from the two surveyed regions was 1.68%, with Alagxa League 4.84% and Hulun Buir 0.56%;statistical analysis showed that there was no significant difference in positive rate of Toxoplasma gondii antibody in sheep between the two areas (P>0.05);no cattle serum samples were found as Toxoplasma gondii antibody positive.[Conclusion] Toxoplasma gondii infection exists in grazing sheep in main pastoral areas of Inner Mongolia. Enough attention should be paid to the prevalence of Toxoplasma gondii infection in free-ranging livestock in this region. In addition, corresponding prevention and control measures are also needed.