This study proposes a novel large mode area fiber structure with bend-resistant and single-mode operation, known as trench-assisted segmented cladding fiber. In this structure, a low refractive index (RI) trench is added to the fiber core and the core is surrounded periodically with high RI fan-segmented claddings. COMSOL software is used to calculate the mode leakage loss and mode area. Numerical analysis indicates that when the indicates bending radius of the fiber is 15 cm, the mode field area of the fiber can achieve 700 μm 2. Meanwhile, the loss ratio between the high-order mode (HOM) and fundamental mode (FM) is >100, which ensures effective single-mode operation. In addition, the fiber performance is stable within the bending orientation from -180° to 180°. Based on the results of this study, the proposed fiber has the potential to play an important role in developing high-power fiber lasers and amplifiers.