A method and an apparatus of re-adjusting convergence of a projection TV are disclosed. The apparatus includes a display device on which an image is projected and at least one light-sensing element (101) being provided around the display device. The light-sensing element (101) is composed of first and second sub-sensors (101a, 101b) that generate separate output signal projected alignment pattern moves over the sub-sensors (101a, 101b). The apparatus further includes a microprocessor calculating a convergence re-adjustment vector by obtaining a location of the light-sensing element (101), from which a previous convergence correction was made. The location of the light-sensing element (101) is obtained by analyzing the output signals. By using the apparatus and method of present invention, the misconvergence of the projection TV can be corrected very quickly and precisely.