Abstract: Weed, as an important component of agricultural ecosystem, is a difficult trouble in organic farming management. Applying different organic fertilizers to change the competitive pattern of weeds may be a new approach for weed control. We aimed to investigate the impact of different tillage and fertilization patterns on weed density, biomass, and biodiversity and crop yield in a temperate organic corn field. We used 5 treatments: no fertilization (CK), cattle dung (CM), earthworm manure (EM), no-tillage (NT) and no-tillage with straw mulching (NS). We found 17 species of weeds in the organic field. CK produced the highest total weed density, but the weed biomass and biodiversity index was lower than with CM and EM. EM produced the highest total weed biomass, and that of Eleusine indica increased by 192.6% and 224.8% (P<0.01) as compared with CK. The species richness and biodiversity index was lower with EM than CK; however, EM produced the highest dominant concentration degree. Total weed density, total weed biomass and biodiversity were lower in NS than in NT. As well, the yield of maize was greater with EM than CK (increased 40.2%, P<0.01) and CM. Thus, the application of cattle dung composted of earthworms could increase the yield of maize and the dominant concentration of weed community in organic farmland.