Because of the powerful data processing ability of FPGA, the fast interpolation algorithm is used for Bayer format data which comes from CMOS sensor MT9M011 to convert to RGB image format. In the RGB color space to YCbCr space conversion stage,using color space conversion formula, combined with the characteristics of FPGA, realize the conversion of RGB to YCbCr. Finally, correctness is verified by the experimental results which use SignalTap II embedded logic analyzer.