The invention provides a motion vector compensation method and a motion vector compensation system for a lost block in video code stream error hiding. The motion vector compensation method comprises the steps of searching the lost block, acquiring a reference frame in a video code stream, searching available blocks around the lost block, searching compensation codes which correspond with the available block in the reference frame, performing structural similarity comparison on the available block and the compensation codes which correspond with the available block, and selecting the motion vector of the available block with highest structural similarity contrast value as motion vector compensation of the lost block. Because the boundary information of the current frame of the lost block is not utilized in a structural similarity evaluation criterion, a problem of low image restoration quality when the lost block is at the boundary or the area with complicated pattern can be well overcome. No matter the position of the lost block in the image, motion vector compensation of the lost block can be accurately obtained by means of the structural similarity evaluation criterion.