Abstract: With colchicine was used as the mutagenic agent, combined with tissue culture techniques, the mutagenesis experiments for bud clump and PLB of Oncidium and the molecular marker technology to detect mutagenesis progeny were studied.Resultsshowed that method of mixed medium supplemented with colchicine was the best way to mutage the Oncidium, and the best condition was 10 dinduction with 500 mg·L-1of colchicine.Plant mutation rate was as high as 26.7%, and there were different mutation forms, such as hairchested, polyphyllous, dwarfed plantlets and widened, thickened leaves, and linear, patterned leaves.Mutant strain went through 5⁶successive transfer culture, and part of them remained properties well.Among them, the variation with golden margin leaves and variation with green margin golden leaves had apparent variation compared with the original species on DNA level by RAPD markers.It suggested a new breeding methods and ideas for Oncidium.