In the previous study, the Agrobacterium tumefaciens- mediated transformation system for rice sheath blight fungus Rhizoctonia solani Kühn was established and a lot of pTHPR1 transformants was obtained in our laboratory. To confirm the biological characteristics of pTHPR1 transformants, 10 verified transformants were selected from the pTHPR1 transformant library. The differences in biological characteristics such as growth rate, colony colour, sclerotial colour, sclerotial number and other aspects between the 10 transformants and the wild type isolate (GD-118) were compared in 5 aspects, i.e. temperature, pH value, carbon sources, nitrogen sources and illumination. The results revealed that the growth rates of these transformants had greater differences when compared with that of the wild type isolate at the following conditions, i.e. cultivation temperature at 25 ℃ and 35 ℃, pH 5.0, pH 7.0 and pH 8.0 of PDA at cultivation phase, glucose and galactose as the carbon sources, glycin as the nitrogen sources, and full dark as the illumination condition. The growth rates of several transformants were faster and the others were slower than that of the wild type isolate. The results also indicated that the sclerotia of transformants had greater differences in both numbers and colours when compared with that of the wild type isolate at the following conditions, i.e. cultivation temperature at 10 ℃ and 35 ℃, pH 4.0, pH 5.0 and pH 6.0 of PDA at cultivation phase,glucose as the carbon sources,sodium nitrate and potassium nitrate as the nitrogen sources,and full dark as the illumination condition. 