High yield of protoplast isolation was achieved from hypocotyls of B. napus L. and leaves of Rorippa indica (Linn.) Hiern. The isolated protoplasts were used to establish an efficient protoplast-fusion system between the two cruciferous species by PEG-DMSO method and culturing with MS liquid medium. Ten somatic fusion hybrids between B. napus and R. indica were obtained. The enzyme combinations for isolating protoplast from B. napus L. and R. indica were 1% cellulase + 0.2% macerozyme + 3 mmol/L MES and 0.25% cellulase + 0.5% macerozyme + 5 mmol/L MES, respectively. Fusion percentage of 10.4% was obtained on the condition of 30% PEG + 0.3 mol/L glucose +50 mmol/L CaCl₂·2H₂O + 15% DMSO. Seeds plants obtained from protoplast fusion are new germplasm derived from R. indica.