Cadmium (Cd) toxicity is a universal environmental threat to plant growth. Either arbuscular mycorrhizal fungi (AMF) or biochar have been shown to effectively mitigate Cd toxicity in plants. Additionally, the camphor tree (Cinnamomum camphora) has been used for phytoremediation of Cd-contaminated soils. However, the potential interacting effects of these treatments and their underlying mechanisms remain unclear. Therefore, we conducted a mesocosm experiment to examine the effects of mycorrhizal inoculation (inoculation with sterilized AMF, with Rhizophagus intraradices and Diversispora versiformis, either alone or their mixture) and/or rice-husk biochar amendment on camphor trees grown in Cd-spiked soils (0, 15, 150 mg Cd per kg soil). We found that Cd addition significantly reduced plant biomass and increased Cd accumulation in plant tissues and soil. Single application of either AMF or biochar significantly inhibited Cd uptake by plants. Nevertheless, AMF inoculation alone improved plant biomass, net photosynthetic rate (Pn), phosphorus (P) uptake and glomalin-related soil protein (GRSP) production, as well as alleviated Cd accumulation in plant shoots to a greater extent than biochar amendment; biochar performed better than AMF in reducing soil Cd mobilization under the highest Cd contamination. These results suggest that AMF and biochar adopt different strategies to reduce Cd toxicity in plants. Moreover, the combination of AMF and biochar showed the highest mycorrhizal colonization, Pn and plant biomass, as well as the lowest Cd uptake by plants under the highest Cd contamination. Particularly, the mixed fungi of R. intraradices and D. versiformis combined with biochar produced the most profound effect on plant biomass under Cd contaminations. These results suggested that the combination of AMF inoculation and biochar amendment had synergistic effects, and their combination performed better than their single application under Cd-contaminated soil. Furthermore, these additive benefits were mainly attributed to the higher total GRSP and mycorrhizal viability. This work suggests that applying mixed fungi of R. intraradices and D. versiformis together with biochar amendment may be a potential method not only for camphor production but also for the phytoremediation of soil exposed to Cd contamination.