The invention discloses a method of improving the image quality during the image zooming process; the window brightness average value and the chromaticity before zooming are calculated to select the macro block subdivision according to the proportion coefficient obtained through the window size before zooming divided by the window size after zooming; the filtration is processed in the selected macro block mode; the image brightness average value and the chromaticity average value after the calculation of the filtration are compared with the window brightness average value and the chromaticitybefore zooming; the steps of edge brightness adjustment and the edge chromaticity adjustment are processed; finally, the image data after the adjustment is outputted. The invention overcomes the defect that the brightness and chromaticity cannot be improved simultaneously during the zooming process of the dynamic video image in the prior art, and provides a method which enriches the image grey gradation and the color gradation performance after zooming, reinforces the light-shade contrast grade and improves the whole image quality; the method can be applied to the video field.