[Objective] The paper was to understand allelopathy of gaseous volatiles of Eupatorium adenophorum stems and leaves on seed germination and seedling growth of Pinus yunnanensis.[Method] P.yunnanensis seeds were treated by fresh stems and leaves of E.adenophorum in translucent airtight container under high concentration( 0.0694g/cm3),middle concentration( 0.0231g/cm3) and lower concentration( 0.0077g/cm3),respectively.[Result] Gaseous volatiles affected seed germination process;with the increasing processing concentration,the day on which seeds began to germinate and the day reaching germination peak were delayed,and the germination quantity on the day reaching germination peak was decreased;the day on which the germination quantity began to significantly reduce was delayed;the process curve was developed from sudden increase and sudden decrease to gentle change,and nearly became a beeline at high concentration.The effects of gaseous volatiles on seed germination( seed germination rate,germination potential,germination index) and seedling growth( fresh weight,dry weight,radicle length,hypocotyl length) of P.yunnanensis were basically consistent,showing a regularity that high concentration had stronger inhibition effect and the inhibition effect became weaker with the decreasing concentration of E.adenophorum.E.adenophorum was widely distributed under P.yunnanensis forests,and might affect natural regeneration and growth of P.yunnanensis via allelopathy.[Conclusion] The paper provides reference for scientific management of P.yunnanensis forests. [Objective] The paper was to understand allelopathy of gaseous volatiles of Eupatorium adenophorum stems and leaves on seed germination and seedling growth of Pinus yunnanensis. [Method] P.yunnanensis seeds were treated by fresh stems and leaves of E.adenophorum in translucent airtight container Under the high concentration (0.0694g / cm3), middle concentration (0.0231g / cm3) and lower concentration (0.0077g / cm3), respectively. [Result] Gurry volatiles affected seed germination process; with increasing processing concentration, the day on which seeds began to germinate and the day last germination peak were delayed, and the germination quantity on the day germination peak was decreased; the day on which the germination quantity began to significant reduce was delayed; the process curve was developed from sudden increase and sudden decrease to gentle change, and nearly became a beeline at high concentration. effects of gaseous volatiles on seed germination (seed germination rate, germination potential, germination index) and seedling growth (fresh weight, dry weight, radicle length, hypocotyl length) of P.yunnanensis were basically consistent, showing a regularity that high concentration had stronger inhibition effect and the inhibition effect weaker with the increasing concentration of E. adenophorum. E. adenophorum was widely distributed under P. yunanensis forests, and might affect natural regeneration and growth of P. yunnanensis via allelopathy. [Conclusion] The paper provides reference for scientific management of P. yunnanensis forests.