RGBG sub-pixel format is widely applied in smartphone nowadays,a hig h-speed RGB-RGBG conversion technology is proposed in this paper for RGBG AMOLED (Active-matrix organic light-emitting diode). The simple conversion pixels and complicated conversion pixels are identified fi rstly,and then direct assignment is applied to simple conversion pixels,while algorithm based on weighting factor i s applied to complicated conversion pixels.There are three innovations:(1) Different from traditional a lgorithm in which all pixels are complicatedly converted,conversion pixel marking method based on the gray level difference among neighboring pixels is firstly proposed in this paper.Complicated conversion is applied to m arking pixels only.Therefore,the conversion speed is enhanced.(2) Direct assignment is applied to simple convers ion pixels,image information is retained because the gray level is not changed.(3) Algorithm based on weighting factors is applied to complicated conversion pixels,the color fringing artifact is weakened while the information loss is minimized.Compared with DA,the value of PSNRU and PSNRV of image proces sed by HSHQ is increased by 7.04% and 6.62%,respectively.Compared with EDMSE,the conversion rate of HSHQ is decreased by 75.63%.Therefore,the conversion speed i s greatly improved while the conversion quality is guaranteed by the proposed al gorithm.