A method for estimating a motion vector of a pixel block, a video processing apparatus, an electronic device and a storage medium. The method for estimating the motion vector of the pixel block includes: obtaining a plurality of candidate motion vectors of a current pixel block in a current video frame, the plurality of candidate motion vectors comprising at least a down-sampled candidate motion vector; calculating a confidence degree for a difference value between each of other candidate motion vectors except for the down-sampled candidate motion vector in the plurality of candidate motion vectors and the down-sampled candidate motion vector; and determining one candidate motion vector in the other candidate motion vectors as the motion vector of the current pixel block, the confidence degree for the difference value between the one candidate motion vector and the down-sampled candidate motion vector is highest.