Abstract: Weed competition is the main factor limiting Angelica sinensis production in cold alpine areas. Combining field investigation with statistical modelling, the weed community dynamics in cultivated fields of the medicinal plant A. sinensis were studied, and compared with those of potato and rape crops. The work was conducted in Zhuoni county of Gannan Prefecture. The aim was to investigate the effect of crop residue characteristics on weed invasion and population change, to provide a scientific basis for defining agricultural residue management practices suitable for cultivation of medical plants, and for development of weed control protocols. The results showed that 15 weed species from 9 families and 15 genera were important. The dominant weed species were Malva sinensis, Senecio vulgaris, Sonchus oleraceus, Stellaria media, Cirsium setosum and Stachys sieboldi. The species, density, diversity and biomass of the weeds all varied with the residue properties and season. Of the two, the seasonal fluctuation was stronger. The diversity of the weed population diminished with time from planting, resulting in stronger competitive impact of the weeds on the crop through a highly similar usage of resources. The weed species M. sinensis and S. vulgaris were especially competitive and established with spring re-greening and spread during development of the Angelica. This pattern was especially prominent in both second-year Angelica crops and potato residues. However, the total weed biomass was the least in rape crop residue, resulting in weak competitive effect against the medicinal. To summarise, the rape residue is the most suitable for Angelica cultivation but it is also pivotal to control the more competitive weeds.