A video image conversion method is for converting interlaced image into progressive image. The deinterlacing method for the video system is for converting the interlaced image into the progressive image. The method performs an interpolation algorithm based on the pixel value of a reference field. An inter-field estimation on the pixel values is performed by referring to a predetermined value to calculate difference value between specific vicinity pixel value and predetermined value, to obtain a set of pixel values, corresponding to the minimum value of summation of a set of pixel difference values. The pixel value corresponding to the auxiliary field is interpolated. The reference field and the auxiliary filed are also referred as the odd field and the even field, where neither the interlacing order nor the respective correspondence is constrained. The method further detects a still motion, such that the flickering is effectively eliminated in another interpolation mode.