The invention discloses silver paste used for a grapheme touch screen, and a preparation method thereof. The silver paste is prepared from flake-like silver powder, spherical silver powder, inorganic electric conduction additive, organic carrier, accessory ingredient and diluent of residual percentage by weight. The preparation method comprises the following steps of: firstly, preparing the organic carrier; adding the flake-like silver powder, the spherical silver powder, the inorganic electric conduction additive, the accessory ingredient and the diluent into the organic carrier; fully and evenly mixing; finally, grinding by a three-roller machine, and carrying out vacuum defoaming. The silver paste disclosed by the invention has the advantages of good overall performance, convenience in printing, good adhesion property, good bending resistance, good weather resistance, good stability and good electrical conductivity and insulating oil performance and can pass a long-time high-temperature high-moisture aging test and thermal shock tests for more than hundred times, and the requirement on the conductive silver paste by the grapheme touch screen can be satisfied.