Littleseed canarygrass (Phalaris minor Retz.) is one of the most troublesome invasive weeds infesting winter crops in the world. Exploring replacement control using higher value crops was thought to be the most potential green control method. Our previous study found that rapeseed was a logical candidate crop to control this weed in agroecosystems, however, the control efficiency of different types of rapeseed (Brassica rape, Brassica juncea and Brassica napus) to the invasive weed littleseed canarygrass were unknown. In this paper, nine rapeseed cultivars of Brassica rape, Brassica juncea and Brassica napus, which occurred in the same region with P. minor, were selected to study their effects on the growth, reproduction, phenotype and allelopathic effects of this invasive weed both in the field and in laboratory experiments. In field experiments, we found that competition modes (intraspecific or interspecific competition) and rapeseed types had significant effects(P=0.0001)on the aboveground biomass, seed number, plant height, branch number, leaf area and special leaf area (SLA) of P. minor, while rapeseed varieties had no significant effects on aboveground biomass (P=0.6064), seed number (P=0.3577), plant height (P=0.4279), branch number (P=0.6357), leaf area (P=0.8839) and specific leaf area (P=0.3424). We also found that the effects of different rapeseed types on P. minor were significantly different, the growth, reproduction and phenotype of P. minor were most affected by Brassica juncea and least by Brassica rape(P<0.05). In laboratory experiments, we found that rapeseeds have strong allelopathy on P. minor, the seed germination, plant height, root length and fresh biomass of P. minor were significantly inhibited when the water extract concentration of the rapeseed leaves was 0.1g/mL. We also found that the allelopthic effects of different rapeseed types on P. minor were significantly different (P<0.05), the species with the strongest allelopathic ability on weed was Brassica juncea under the same conditions. Together, the control efficiency of different rapeseed types on invasive weed P. minor were significant differences, and the control effect of Brassica juncea was better than that of Brassica rape and Brassica napus, its strong allelopathic characteristics may play an important role in replacement control. In addition, our study also suggest that replacement control by different rapeseed varieties is potentially a feasible and sustainable means of suppressing littleseed canarygrass.