[Background] Chromolaena odoratum (L.) R. King et H. Rob. is one of the most serious invasive weeds in China. There exists no currently available, sustainable control technology.[Method] Competitive effects were studied between C. odoratum and four forage grasses, Pennisetum americanum×P. purpureum, Cajanus cajan (Linn.) Millsp., Tephrosia candida DC., and Paspalum wettsteinii Hackel. Using the De Wit's method, replacement series at the densities of 2 plants·pot^-1 (42.42 plants·m^-2), 4 plants·pot^-1 (84.84 plants·m^-2), and 8 plants·pot^-1 (169.68 plants·m^-2) were planted to determine their potential of controlling C. odoratum.[Result] P. americanum×P. purpureum and C. cajan inhibited the growth of C. odoratum significantly and the competitive balance indexes (CB) of P. americanum×P. purpureum and C. cajan were significantly higher than 0 at three densities, suggesting that P. americanum×P. purpureum and C. cajan had strong competitiveness. The relative yields (RY) of T. candida and P. wettsteinii were all less than 1 and their CB were significantly below 0 at three densities, indicating that these plants have weaker competitiveness than C. odoratum.[Conclusion] P. americanum×P. purpureum and C. cajan are potentially appropriate as replacement plants against C. odoratum.