Strategic fertilizer management is an important component of integrated weed management systems，and the P in the soil is one of the most important factors determining the growth and competitive advantage of invasive plants.A controlled trial in pots was conducted to investigate the effect of P addition on the growth and competitive ability of the invasive plant Aegilops tauschii under high N conditions.The results showed that:(1)P addition caused some effects on the growth and competition of both Aegilops tauschii and wheat under high N conditions.The plant height，leaf area，tiller number and total biomass of Aegilops tauschii in the monoculture model showed a increasing trend with the increase of P addition under high N conditions.Based on the increase of the above indicators，the responsiveness of Aegilops tauschii to P addition under high N conditions was greater than that of wheat.The root to crown ratio of Aegilops tauschii increased while the leaf area root mass ration showed a continuous decrease with the increase of P addition，and this indicated that it adapted to the change of P addition under high N conditions by increasing the input to the roots，and this may be the result of the high demand for N in Aegilops tauschii caused by P addition，and the high N conditions in the experiment could not meet its growth and development needs.(2)The mean plasticity indices of seven indicaters including plant height，leaf area and others seven indicators of Aegilops tauschii were 0.31 and 0.48 for the monoculture model and mixed-culture treatments，which were significantly higher than those of 0.25 and 0.43 in wheat，respectively，and this suggests that Aegilops tauschii adapts with relatively high plasticity to changes in P addition under high N conditions.(3)The competitive balance value of Aegilops tauschii was greater than 0 and showed a gradual increase，and this suggests that P addition under high N conditions increased the competitive inhibition of wheat by Aegilops tauschii.In summary，unscientific phosphorus fertilizer management may further exacerbate the competitive harm of Aegilops tauschii to wheat in the context of the increasing N content in soils of winter wheat fields at present.