To obtain the artificially induced 2n pollen from the diploid Chinese ancient rose ‘Old Blush’, which is to be used for the crossbreeding of modern rose and to effectively make use of its genetic resources, based on the understanding of the development of pollen mother cell of ‘Old Blush’, this study used the method of colchicine injection combined with wrapping to treat the tender buds, and we successfully obtained the 2n pollen which could be normally germinated. The performance of induced 2n pollen for cross breeding was also evaluated by observing the germination characteristics in vitro and on the pistil. The results showed that: (1) the colchicine absorbent cotton wrapping caused the death of part of the buds before the pollination, and the survival rate of flower bud decreased equally significantly with the increase of colchicine concentration and treatment time. (2) The 2n pollen induction rate differed significantly between the four colchicine concentrations of 2.5 g/L, 5.0 g/L, 7.5 g/L, and 10.0 g/L, but did not differ significantly between the three treatment periods of 24 h, 48 h, and 72 h. The best treatment was 24hour 5.0 g/L colchicine, which can produce 15.83% viable 2n pollen. The 2n pollen vitality of this treatment was 27.2% detected by Alexander staining. (3) The mother cell of ‘Old Blush’ pollen had abnormal lagging chromosomes and parallel spindle during meiosis. During the tetrad period, dyads and triads were formed whose number of chromosomes are doubled, and the 2n pollen was produced eventually. (4) The in vitro germination rate and pollen tube length of induced 2n pollen were insignificantly different from those of natural pollen, and both of them could germinate on the stigma of female parent and grow pollen tubes in the ovary, so they could be used for a further crossbreeding.