Abstract: In order to explore seed germination characteristics of three species of Cynanchum including Cynanchumthesioides, Cynanchum chinensewere and Cynanchum hancockianum and find the positive priming that could significantly promote seed germination and seedling establishment under drought stress, the wild seeds of three species were used as test materials, their germination parameters（germination percentage, germination potential, germination index, etc.） and seedling establishment parameters（root length and bud length） under different priming treatments were measured. Three priming with the highest effect were selected for subsequent test of drought stress by comprehensive analysis of membership function, which could provide theoretical basis for subsequent artificial introduction, cultivation and practical production. The results indicated that the natural germination percentage of C. thesioides, C. chinensewere and C. hancockianum were 52.67%, 93.33% and 90.00%, respectively. The appropriate priming could significantly promote seed germination and seedling establishment. Membership function analysis showed that three solutions with the highest priming effect for C.thesioides and C. hancockianum were H₂O（S1）, 0.3%H₂O₂（S4） and 5%PEG（S5）, and for C.chinensewere were 0.5%KMnO₄（S2）, 0.3%H₂O₂（S4） and 5%PEG（S5）, respectively. In addition, the appropriate seed priming could alleviate the germination restriction caused by drought stress, among which 0.3%H₂O₂ had the best effect, the germination percentage of three species of Cynanchum increased by 83.00%, 18.10% and 21.29% compared with the control（S0N1）, respectively, which was suggested to be used as an effective seed priming in subsequent research and practical production.