The invention discloses an image noise reduction method based on an image block prior estimation mixed framework, and specifically relates to prior estimation of image blocks, and an image noise reduction method. The prior estimation involves classifying the image blocks through detecting image structures and performing image noise reduction on the classified image blocks according to different image results by using an image block expected logarithm likelihood estimation and an image block coupling-three-dimensional filtering method. According to the invention, by use of the image noise reduction method based on the image block prior estimation mixed framework, noise reduction can be realized relevantly according to different image block structures, and experiment results show that the method, compared to other noise reduction methods, has the advantage of better-robustness noise reduction.