Table 1 shows the frequencies of chromosome doubling of diploid, triploid and tetraploid of Phal. aphrodite subsp. formosana and diploid of Phalaenopsis bellina produced by the method in accordance with the present invention. As can be seen in Table 1, the frequencies of chromosome doubling are different in different generations of regenerated plants of the diploid, the triploid and the tetraploid of Phal. aphrodite subsp. formosana and the diploid of Phalaenopsis bellina. The average frequency of the protocom generation is only 0.7% but the average frequencies of first to third cutting generations are 11.4%, 31.4% and 44.0%, repectively. It is found that the different species or different lines of the same species having different ploidy levels processed by the method of the present invention can be successful in achieving a higher degree of frequency of chromosome doubling. The frequency of chromosome doubling can trend to increase as its generation (i.e. the number of cutting) increases.