Abstract: Resistance of 5 strains of Rhizoctonia cerealis to validamycin collected from 4 wheat-growing areas was measured by using mycelium growth rate method. A sensitive strain of the fungus was subcultured on the media containing validamycin to induce the resistance development of the strain of R.cerealis,the cross resistance of the resistant strain to other fungicides was studied. The sensitivity of R-strain and S-strain to osmolarity,also the difference of reducing sugar and soluble protein in culture liquid of R-strain and S-strain after treatment with validamycin,were compared.The results showed that the resistance level of 5 strains ( L2,L1,TA,TW,and JZ) to validamycin was 7.26-,7.75-,10.46-,14.92- and 23.31-fold, respectively. After 36 subcultured on PDA containing validamycin in laboratory ,the resistance level of Rhizoctonia cerealis reached 49.24-fold to validamycin,the R-validamycin strain was gained. The resistance level of resistant strain of R.cerealis to difenoconazole,thiram,tridimefon,propiconazole,tebuconazole,fludioxonil was 48.58-,21.78-,17.62-,10.95-,2.55- and 1.78-fold,respectively. Inhibition rate of R-strain was higher than S-strain in the PDA containing 1% and 4% dextrose. In addition,the results of electrolyte leakage showed that the electrolyte of R-stain and S-strain was seriously exosmosised after treatment with validamycin,and the R-strain could leak more electrolyte than the S-strain in 10 h.