【Objective】The present experiment was conducted to investigate the optimal chromosome preparation technique of P. yunnanensis Dode root-tip cell， in order to provide references for identification of P. yunnanensis Dode’s chromosome number and its genetic improvement. 【Method】Taking test-tube plantlet root tip of P.yunnanensis Dode as materials， the conventional chromosome preparation method was used to optimize pretreatment solution，pretreatment time，fixing time，type of dissociated solution， dissociated time and dyeing time， in order to obtain optimal chromosome preparation effect. Besides， the chromosome number of P. yunnanensis Dode was identified. 【Result】After being pretreated in saturated p-dichlorobenzene solution at 0 ℃ for 1.0 h，the root-tip materials were fixed in Carnot solution for 1.0 h at 0 ℃. Then，these materials were dissociated in mixed solution（concentrated hydrochloric acid∶anhydrous ethanol=1∶1） for 4 min at room temperature. In addition， after being dyed in modified Carbol fuchsin solution for 9 min， the clear and favorable chromosome images with good dyeing effect were obtained with traditional squash methods. Furthermore， the chromosome number of P. yunnanensis Dode was 2n=2X=38 through observing with microscope. 【Conclusion】The established root-tip chromosome preparation technique system of P. yunnanensis Dode can make root-tip chromosome number be observed quickly and clearly， so as to obtain favorable chromosome images with good dyeing effect.