The invention discloses a porcine streptococcus disease and haemophilus parasuis disease combined inactivate vaccine and a preparation method thereof. The preparation method comprises the following steps of: a, respectively carrying out enrichment culture on a porcine streptococcus strain, a haemophilus parasuis strain and a haemophilus parasuis strain to obtain a porcine streptococcus strain bacterial solution, a haemophilus parasuis strain bacterial solution and a haemophilus parasuis strain bacterial solution; b, respectively adding a formaldehyde solution into the porcine streptococcus strain bacterial solution, the haemophilus parasuis strain bacterial solution and the haemophilus parasuis strain bacterial solution, and inactivating; c, mixing the collected porcine streptococcus strain bacterial solution, the haemophilus parasuis strain bacterial solution and the haemophilus parasuis strain bacterial solution, adding Tween-80 for preparing a water phase, preparing white oil, Span-80 and aluminium stearate into an oil phase, mixing the water phase with the oil phase to prepare a uniform emulsion, i.e. an oil emulsion inactivating vaccine; and 4, sub-packaging the oil emulsion inactivating vaccine. The porcine streptococcus disease and haemophilus parasuis disease combined inactivate vaccine can effectively prevent the porcine streptococcus disease and haemophilus parasuis disease, does not have hidden danger of scattering viruses and is safe and reliable; and the immunization is realized by one vaccine, thus the cost is reduced.