A video processing method enlarging and enhancing sharpness of input video data includes following steps. First, N sets of pixel row data of the input video data are respectively buffered in N linear buffers, N is a natural number. Next, I sets of enlarged pixel row data are generated by interpolation according to the buffered N sets of pixel row data in the N linear buffers and a currently inputted set of pixel row data, I is a natural number greater than N. Then, I sets of smoothed and enlarged pixel row data are generated according to the buffered N sets of pixel row data in the N linear buffers and the (N+1)th set of pixel row data. Thereafter, I sets of sharpness-enhanced pixel row data are obtained according to the I sets of enlarged pixel row data and the I sets of smoothed and enlarged pixel row data.