In the preferred embodiment, in sixth step (f) the regenerating medium is suitable for inducing and differentiating the next-generation PLB into orchid plantlets. The regenerating medium is selected from a solid medium or a liquid medium. In a preferred embodiment, the solid medium is selected from inorganic salts (e.g. MS basal salts and Hyponex No. 1), saccharides, organic suppliments (e.g. tryptone or peptone), gelling agent (e.g. agar) and plant growth regulators. Preferably, the plant growth regulators are selected from the groups consisting of: auxins, cytokinins and combinations thereof. In general, the amount of the growth regulators in the regenerating medium used in the present invention is less than that of the inducing medium. Alternatively, the plant growth regulators can be substituted by natural additives. The natural additives applied in the present invention contains, but not limit to, homogenized potato, homogenized banana and/or coconut water etc. The ingredients of the liquid medium applicable to the present invention are the same with those of the solid medium, and no gelling agent is added in the liquid medium.