Abstract: Objective: Carbody structure weight reduction is faced with bottlenecks. It is needed to achieve weight reduction through reasonable selection of carbody materials. In this regard, a weight reduction scheme for 100% lowfloor light rail vehicle of CFAA (carbon fiber and aluminum alloy) material hybrid carbody is proposed. Method: A fully welded aluminum alloy carbody for 100% lowfloor light rail vehicle is taken as a comparison object. The structure and the materials used for each component of the carbody are analyzed, and static strength simulation analysis is conducted on aluminum alloy carbody. Based on the stress level of each major component, a CFAA material hybrid carbody scheme is proposed according to the principles of material weight reduction and safetyreliability. In the scheme, the vehicle underframe with higher stress level still uses aluminum alloy profiles, while other components such as side walls, roof and end walls use carbon fiber + PVC (polyvinyl chloride) foam composite materials. The grade of selected carbon fiber is T300, and rivet joints are used to connect large carbon fiber components. According to EN 126631: 2010, static strength simulation analysis is carried out on the CFAA hybrid carbody structure, and the inplane stress strength factor is calculated using the TsaiWu strength criterion to evaluate the hybrid carbody. The advantages of carbon fiber material and precautions on carbody application are summarized. Result & Conclusion: The weight of CFAA material hybrid carbody is reduced by more than 15% compared to the fully welded aluminum alloy carbody. The simulation results show that the strength of CFAA hybrid carbody meets the requirements. It is demonstrated that the use of CFAA material hybrid carbody meets the requirements for both lightweight design and strength.