The invention provides preparation methods of a polarizer binder and a low-blue-light polarizer. The preparation method of the polarizer binder comprises the steps of preparing a first colloidal swelling material, and adding a second colloidal swelling material of a heterocyclic compound or metal halide capable of causing the blue shift of an iodide ion spectrum; preparing a binder precursor; mixing a crosslinking agent, a radical initiator and the binder precursor to obtain the polarizer binder. The low-blue-light polarizer is bound by the polarizer binder and treated at high temperature. According to the preparation method of the low-blue-light polarizer, by adjusting a spectrum of the polarizer in the direction of a blue primary color light stimulation value function, the low-blue-lightpolarizer capable of reducing the sensation degree of the human eyes to blue primary light is finally obtained; since the binder does not contain a water-insoluble ultraviolet absorbent, appearance defects such as foreign matter, point defects and scratches and optical problems such as reduction of the degree of polarization cannot occur, and the appearance and optical performance of the polarizer finished product are excellent.