An image data correction method and apparatus for a plasma display panel, and a plasma display panel device having the apparatus. The image data correction method calculates a load factor of video signals fed into a plasma display panel, and determines an automatic power control level corresponding to the calculated load factor. The method further involves generating sustain pulse information and the number of subfields and selecting a correction table corresponding to the number of subfields and the automatic power control level from the memory. Then, the image data is corrected with reference to the correction table. By this image data correction, white chromaticity can be maintained constantly while enhancing the color reproducibility of each subfield.