The invention relates to an image quality enhancement and filtering method applied to a CMOS image sensor. According to the method, interpolation processing on original Bayer data outputted by the image sensor is carried out, and a pixel value of a three primary color RGB space is acquired; the pixel value of the three primary color RGB space is transformed to be YUV space; a contrast ratio of a Y channel is adjusted; saturation of U and V channels is adjusted; secondly, hybrid noise reduction processing is carried out; lastly, edge sharpening processing on the Y channel is carried out, and the image later processing data is outputted; the three primary colors RGB refer to red, green and blue three primary colors, the YUV space refers to chrominance space, the Y refers to brightness, and the U and the V refer to aberration. Through the method, a pipelining grade design idea is employed, the image data is not stored, only one-dimensional space image enhancement and noise reduction processing on the Bayer data after interpolation are carried out, technology processing performance is relatively good, complexity is low, the method facilitates hardware realization, and occupied chip sources are a few.