The invention discloses a contraposition method for an OLED (organic light emitting diode) mask board, facilitating the contraposition between unit devices on the mask board and pixel units on a glass substrate. The method comprises the following steps: A: dividing the whole mask board to a group of daughter boards; B: fixing the daughter boards on subframes; C: distributing the daughter boards in parallel on a main frame, and arranging a motion mechanism between every subframe and the main frame; and D: arranging the glass substrate below the main frame, utilizing the motion mechanisms to drive the subframes to move the daughter boards, and enabling the positions of unit devices on the auxiliary plates to correspond to those of the pixel units on the glass substrate. By using the method,the corresponding daughter boards are replaced instead of the whole mask board when the position of a unit device can not correspond to the pixel unit, so that the material economization is facilitated and the production cost is reduced.