Hybridization of invasive plants with native plants may alter their traits and enhance their tolerance to some heavy metals by affecting their physiological and biochemical processes. Cadmium (Cd) is one of the main heavy metal elements currently causing soil pollution. To investigate whether hybridization can enhance the tolerance of plants to cadmium, we used a filter paper to compare germination and seedling growth of Xanthium strumarium, X. sibiricum, and their hybrids (X. strumarium♀×X. sibiricum♂ and X. sibiricum♀×X. strumarium♂) under different concentrations of Cd (0, 10, 40, 80, and 120 mg/L). The results showed that:1) hybrids of X. strumarium and X. sibiricum exist in nature; 2) Cd promotes the germination of seeds of X. strumarium♀×X. sibiricum♂; when the Cd concentration was 80 mg/L, the germination rate, germination potential, and germination index of X. strumarium♀×X. sibiricum♂ were the highest; 3) the root length and chlorophyll content of X. strumarium♀×X. sibiricum♂ were lower than those of X. strumarium under 80 mg/L and 120 mg/L Cd, but the oxidative stress of cotyledons of X. strumarium♀×X. sibiricum♂ was less than in X. strumarium. These results show that hybridization may increase the transport ability of Cd in X. strumarium under high concentration of Cd. The roots of the seedlings absorb a large amount of Cd and transport it up to the cotyledons, which leads to inhibition of root growth and decreased chlorophyll content of cotyledons. The antioxidant enzyme system may play an important role in reducing the degree of cotyledon oxidation.