The present invention provides an image processing circuit, wherein the image processing circuit comprises a receiving circuit, an image dividing circuit, a first image enlargement circuit, a second image enlargement circuit and an output circuit. In the operations of the image processing circuit, the receiving circuit receives image data, the image dividing circuit divides a pixel value of each pixel of the image data into two parts to generate first image data and second image data, the first image enlargement circuit enlarges the first image data in a linear manner to generate enlarged first image data, the second image enlargement circuit enlarges the second image data in a non-linear manner to generate enlarged second image data, and the output circuit generates an output image according to the enlarged first image data and the enlarged second image data.