Abstract: Two kinds of specific and sensitive methods for detecting Toxoplasma gondii was estab-lished by means of NT-PCR and One-Tube Hemi-Nested PCR. The DNAs were extracted from Toxooplasma gondii、Giardia lamblia and also blood、brain、liver、spleen、lung、kidney tissue of ICR mice infected with Toxoplasma gondii by routine methods. Two DNA fragments of the expected size （522 bp and 362 bp） was ampliflied from Toxoplasma gondii、blood、brain、liver、spleen、lung and kidney tissue by using NT-PCR and Hemi-Nested PCR rspectivelly, but no band was observed in Giardia lamblia. The sensitivity of the reaction was determined with different concentrations of genomic Toxoplasma gondii DNA，the DNA even less then lpg could be detected by us-ing single-step PCR.The NT-PCR or One-Tube Hemi-Nested PCR was more sensitive than sin-gle-step PCR.

Key words: Toxoplasma gondii, Single-step PCR, NT-PCR, One-Tube Hemi-Nested PCR