Studies on influence of harvesting period during the year and storage time on inhibitory effect of aqueous extract of shoot tip of Acacia pennata (L.) willd.Subsp.Insuavis Nielsen.were evaluated on seed germination and seedling growth of wild pea (Phaseolus lathyroides).A.pennata shoot tip were harvested on day 15th of each month from January to December, 2010.Harvested shoot tip from each month was dried up by a hot-air oven at 45℃ for 5 days, then extracted with distilled water and bioassay.Shoot tip aqueous extract from A.pennata harvested in March to July was the most inhibitory effects, at the concentration of 1.25% (w/v) caused completely inhibited germination of wild pea seed, harvested in January to February showed moderate inhibitory effect (70 to 80%inhibition) and harvested in August to December showed less inhibition effect (20 to 50%inhibition).In order to evaluation of storage time affecting inhibition potential of aqueous extract from A.pennata, shoot tip was harvested on May 15, 2010 and storage in dark bag at room temperature.Storage shoot tip sample was collected at 0, 7, 30, 60 and 90 days after storage, extracted with distilled water and bioassay on germination and seedling growth of wild pea seed.At 1.25% of aqueous extract of shoot tip from A.pennata germination percentage of wild decreased with increasing storage times.Aqueous extract at 0 and 7 days after storage completely inhibited seed germination, while inhibitory effect of aqueous extract from 30 and 60 days after storage were decreased to 55% and 40%, respectively and germination of wild pea seed was completely germinate by aqueous extract at 1.25% from shoot tip after 90 days storage time.