The invention discloses a codebook design method for resisting passive eavesdropping in an MISO system based on a weighting Voronoi graph. The method comprises the steps of 1, taking optimum beam forming on theoretical significance and a corresponding traversal safety rate as references for measuring a safety performance loss; 2, calculating the traversal safety rate after adoption of quantified beam forming, and through combination of the traversal safety rate, obtaining a traversal safety rate loss; 3, defining and calculating a traversal nonzero safety rate loss according to the traversal safety rate loss, and carrying out optimization to obtain an upper bound and a corresponding codebook design standard; 4, establishing the weighting Voronoi graph in complex field Grassmann flow pattern space according to the codebook design standard; 5, with a purpose of minimizing the traversal nonzero safety rate loss, establishing an iterative algorithm VQ-WVD through adoption of an iterative offline training mode, and realizing the weighting Voronoi graph in the complex field Grassmann flow pattern space, generating code words, and obtaining a codebook based on the VQ-WVD.