1. An offset method of a RGBW panel subpixel, comprising: inputting data of pixels based on RGB color space in an image; determining the most similar pixels of each of the pixels in the image according to the data of pixels based on RGB color space; when resolution of pixels is the same, converting the data of the pixels based on RGB color space to data of the pixels based on RGBW color space, determining data based on RGBW color space corresponding to the most similar pixels of the pixels; three fourths subsampling the pixels in the image according to the data of the pixels based on RGBW color space, the data based on RGBW color space corresponding to the most similar pixels of each of the pixels; outputting data of pixels in the image after being sampled; wherein the sequence of determining the most similar pixels of each of the pixels in the image according to the data of pixels based on RGB color space comprises: converting the data of the pixels based on RGB color space to data of the pixels based on HSI color space; calculating similarity of each of the pixels and adjacent pixels according to the data of the pixels based on HSI color space, achieving the most similar pixels of the each of the pixels; wherein the sequence of three fourths subsampling pixels in the image according to the data of pixels based on RGBW color space, the data based on RGBW color space corresponding to the most similar pixels of each of the pixels comprises: dividing pixels in the image in an order of each group consisting of four pixels in the RGBW color space; adjusting arrangement of 16 subpixels in each of the groups, an arrangement of the 16 pixels in each of the groups after adjustment: RGBW, WRGB, BWRG, GBWR; three fourths subsampling the 16 subpixels of each of the groups according to the arrangement of the 16 subpixels of each of the groups after adjustment, achieving arrangement of 4 three-channel subpixels of each of the groups: RGB, WRG, BWR, GBW, wherein when the pixel i is RGBW, a strategy for sampling is: R d ( i ) = P r ( i ) G d ( i ) = G o ( i ) B d ( i ) = B o ( i ) , when the pixel i is WRGB, a strategy for sampling is: W d ( i ) = P w ( i ) R d ( i ) = R o ( i ) G d ( i ) = G o ( i ) , when the pixel i is BWRG, a strategy for sampling is: B d ( i ) = P b ( i ) W d ( i ) = W o ( i ) R d ( i ) = R o ( i ) , when the pixel i is GBWR, a strategy for sampling is: G d ( i ) = P g ( i ) B d ( i ) = B o ( i ) W d ( i ) = W o ( i ) , R d (i), G d (i), B d (i) and W d (i) are respectively grey levels of the pixel i based on four channels RGBW on RGBW color space after being sampled, R o (i), G o (i), B o (i) and W o (i) are respectively grey levels of the pixel i based on four channels RGBW on RGBW color space before being sampled, P r (i) is achieved according to R s (i), R o (i) and R o (i−1), P w (i) is achieved according to W s (i), W o (i) and W o (i−1), P b (i) is achieved according to B s (i), B o (i) and B o (i−1), P g (i) is achieved according to G s (i), G o (i) and G o (i−1), R s (i), G s (i), B s (i) and W s (i) are grey levels of the RGBW four channels on the RGBW color space corresponding to the most similar pixel of the pixel i, R o (i−1), G o (i−1), B o (i−1) and W o (i−1) are grey levels of the RGBW four channels on the RGBW color space based on the pixel i−1 before being sampled.