The invention discloses a frame rate up-conversion method based on the mixed matching of chromaticity, used for improving the visual quality of a video sequence. The method comprises the steps of firstly designing a block matching criterion by using a chromaticity mixed matching model, wherein the block matching criterion can reflect the level of a difference between the brightness of the video sequence and a chromatic aberration channel; then using an improved three-dimensional recursive search method to compute forward and backward initial motion vector fields, on the basis, providing a time-space motion vector purification method, implicitly adding time-space smooth constraint into the motion vector purification method, and thus obtaining a smoother motion vector field; then providing a high fault-tolerant motion vector smoothening method to inhibit abnormities existing in the motion vector fields; and at last, in order to reduce edge blurring and shielding problems, providing a double-weighted overlapped block motion compensation method, and using the forward and backward initial motion vector fields to jointly generate an interpolating frame. According to the method, the subjective and objective quality of the interpolating frame can be significantly improved, and the low computation complexity is ensured.