Thermoelectric materials have garnered considerable attention due to their unique ability to directly convert heat to electricity and vice versa. Polymers carry many intrinsic advantages such as low thermal conductivity, solution processability, and roll-to-roll production for fabricating high-performance, light-weight, and flexible thermoelectric modules. In this review, we highlight recent advances in the preparation, modification and optimization of polymer thermoelectric materials, focusing especially on the current state-of-the-art strategies to minimize the thermal conductivity and maximize the power factor, and finally provide an outlook on the future development of this field.