The invention provides an attaching method and device for polarizers. The equipment comprises a backlight source, a liquid crystal box fixing unit, a polarizer adjusting unit, a detection unit and a control unit. When the polarizer attaching device works, the backlight source is electrified and a liquid crystal box is electrified to output detection images. The polarizer adjusting unit drives the polarizers to rotate around the central shafts of surfaces of the polarizers at the pre-set interval angles. The detection unit detects detection images of the polarizers at the current rotary position and transmits the detection images to the control unit. The contrast ratios are calculated according to the detection images of the polarizers at the current rotary position by the control unit. When the contrast ratios of the polarizers at the current rotary position are less than those of the detection images of the polarizers at the former rotary position, a judgment is made that polarization angles of the polarizers at the former rotary position highly coincide with the polarization angle of the liquid crystal box so that the attachment positions of polarizers at the current rotary position are determined. The attached products possess high contrast performance.