A Progressive Graphic File(PGF) compression encoder based on xDM standard was presented for the real-time image compression of a solar image.The PGF compression algorithm with advantages of natural image compression and compression speed was analyzed and customized.According to the interfaces required by xDM standard,a PGF compression encoder was designed.Aiming at the features of the DaVinci hardware architecture,the PGF compression encoder was optimized on many aspects such as software design,C language program and linear assembly language program.Finally,a real-time online test was carried out for the performance parameters on compression ratio,compression time and SNR of the PGF compression encoder.The experimental result shows that the speed of the optimized PGF compression encoder is 18.7 times that of original one,which can fully meet the design requirements of the real-time image processing system of a solar telescope.