The novel rice ( Oryza sativa L.) line YSBR1 is an intersubspecies hybrid with high level of partial resistance to sheath blight (SB). For the purpose of assessing the resistant level of YSBR1 using multiple approaches, the disease score of YSBR1 was investigated after artificial inoculation in the field and greenhouse in 2006 and 2007. The inhibition rate SB-toxin to the embryo root was also used as a criterion of SB resistance. Compared with other rice genotypes, YSBR1 had significantly higher resistance to SB and the resistance was stable and reliable. The average SB disease score of YSBR1 was 2.39±0.23 and felt in “resistant” grade in the “0–9” rating system when the susceptible control Lemont showed a mean disease score of 7.55±0.26. Correlation analysis showed that the SB-toxin inhibition rate was significantly correlated with disease score from the field test. The SB-toxin inhibition rate of YSBR1 was 57.55%, which was similar to that of Jasmine 85 but significantly lower than that of other tested varieties and Lemont (97.39%). In addition to the high resistance to SB, YSBR1 is also in good performance of plant type and height, growth duration, and grain yield, indicating its prosperous application in variety improvement of SB resistance in rice breeding programs.