Tausch's goatgrass (Aegilops tauschii Coss.), an annual or perennial grass weed, is an invasive alien species and a close relative to wheat (Triticum aestivum). The morphology and biological characteristics of Tausch's goatgrass is very similar to wheat. It becomes a serious problem weed in wheat fields due to strong competitive ability with wheat for water, light, nutrients and space. Now, an estimated 330000 hm² of winter wheat fields are infested in Hebei, Henan, Shanxi, Shandong, and Shaanxi provinces. Lack of efficient herbicides and easily spreading with wheat seeds made it will be the worst weed species in winter wheat fields. The occurrence of Tausch's goatgrass and its competitive effect on the growth of winter wheat were studied in Shandong, Hebei, and Henan provinces, from 2009 to 2011. The dynamics of emergence, tillering, plant height and fresh weight of Tausch's goatgrass were highly temperature dependant. There were two main peaks of seedling emergence for Tausch's goatgrass, one before winter, from late October to early November, and the other in spring, from late March to early April. In late October to early November, the weekly average temperature was between 16.2 and 11.6 ℃. During this period, Tausch's goatgrass reached the highest seedling emergence rate of 218.7 plants/m² per week, accounting for 27.2% of the total annual emergence in Feicheng of Shandong province. Tausch's goatgrass seedlings did not emerge when the weekly average temperature was below 5 ℃. The amount of seedling emergence before winter accounts for 87% of the total annual emergence. At 35 d after wheat seeding, Tausch's goatgrass and wheat simultaneously entered the tillering stage and alternately reached the tillering peak. Their tillering ended in early December, when the weekly average temperature was between 3.4 and 11.9 ℃. Tausch's goatgrass formed 5.1, 4.2, and 4.4 tillers per plant in Shandong, Hebei, and Henan provinces, respectively. It developed more tillers than wheat, which developed 3.8, 3.2, and 3.2, for each province, respectively. The tillering ability of Tausch's goatgrass is stronger than wheat, developing 3.0, 3.4 and 2.2 more effective tillers than wheat in Shandong, Hebei and Henan province, respectively. The ear density of wheat compared to Tausch's goatgrass showed a negative correlation, where an increase of ear density of Tausch's goatgrass was reflected by a gradual reduction of the ear density of wheat. The impact of Tausch's goatgrass on wheat yield was primarily through inhibiting the effective ears of wheat. It had no significant effect on 1000-seed weight. When Tausch's goatgrass density reached 640 spikes/m², the yield of wheat decreased by 28.38%.