A pot experiment was conducted to study the effects of intercropping with positive and negative grafting offspring of two ecotypes (farmland and mining) of cadmium (Cd) hyperaccumulator plants Galinsoga parviflora on Cd accumulation of lettuce. The positive grafting: the rootstock was mining ecotype of G. parviflora (grafting offspring was defined as mining-rootstock) and the scion was farmland ecotype of G. parviflora (grafting offspring was defined as farmland-scion); the negative grafting: the rootstock was farmland ecotype of G. parviflora (grafting offspring was defined as farmland-rootstock) and the scion was mining ecotype of G. parviflora (grafting offspring was defined as mining-scion). The results showed that compared with the monoculture of lettuce, only farmland-scion and mining-scion increased the root and shoot biomasses of lettuce (intercropping with mining-scion had the maximum of shoot biomass, increased by 10.98% compared with the monoculture), but the other treatments inhibited the growth of lettuce. In addition, intercropping with farmland-scion and mining-scion also significantly improved POD and CAT activities but had no obvious effects on SOD activity of lettuce. Compared to the monoculture of lettuce, intercropping with grafting offspring of G. parviflora significantly reduced Cd contents in shoots of lettuce, and intercropping with mining-scion had the minimum content, reduced by 29.18% compared with the monoculture. Therefore, intercropping with mining-scion not only effectively reduced Cd contents in the edible parts (shoots) of lettuce, but also promoted the growth of lettuce.