An image format conversion system includes a horizontal filter to receive an image input signal with a frequency of a first clock signal in order to perform a filtering operation to thereby produce a horizontal filtering image signal; a first FIFO to temporarily store the horizontal filtering image signal; a 2D image interpolator to perform a deinterlacing, a vertical interpolation and a horizontal interpolation operations on the horizontal filtering image signal to further produce a scaled progressive image signal; a second FIFO connected to the 2D image interpolator to temporarily store the scaled progressive image signal; an interpolation clock controller to receive a second clock signal and produce multiple enable signals in order to enable the horizontal filter and the 2D image interpolator, wherein the second clock signal has a frequency independent of the frequency of the first clock signal.