The photocatalysis-Fenton technology coupling can efficiently degrade organic pollutants. In this study, Fe(III)-doped rGO/Bi₂MoO₆ composite catalyst (Fe(III)/rGO/Bi₂MoO₆) was prepared by solvothermal method, and the photocatalysis-Fenton synergy system was constructed by adding H₂O₂. The phenol degradation activity under 3 h visible light irradation is 82%, much higher than that of photocatalysis alone (18%) or renton reaction (48%), and further optimization can achieve full degration of phenol. This can be mainly attributed to the transformation of the valence state through the gain and loss of Fe electrons, which serves as a bridge to realize the photocatalysis- Fenton synergy. Meanwhile, the excellent electrical conductivity of graphene overcomes the difficulty of separating photo-generated electron holes in photocatalysis, and promotes the cyclic reaction of Fe³⁺/Fe²⁺, and then accelerates the Fenton reaction to produce more free hydroxyl groups (•OH), which further improves the degradation efficiency. Effects of Fe(III) content, catalyst dosage, H₂O₂ content, and pH on the synergy degradation performance were investigated. The quenching experiment proves that •OH is one of the main active species in the degradation system, while •O₂^- and H⁺ also have a certain effect on the degradation activity. The mechanism of Fe(III)/rGO/Bi₂MoO₆ photocatalysis-Fenton synergy degradation is also proposed based on the present experimental results.