The invention discloses a titanium tungsten silicon composite powder used for diesel vehicle/steamship tail gas SCR denitration, and a preparation method thereof, and belongs to the field of carrier coating material. The titanium tungsten silicon composite powder used for diesel vehicle/steamship tail gas SCR denitration is capable of avoiding defects of conventional SCR catalysts. The preparationmethod comprises following steps: metatitanic acid is subjected to beating dispersion, and ammoniacal liquor is added to adjust pH value so as to obtain a slurry; metatitanic acid is subjected to beating dispersion, ammoniacal liquor is added to adjust pH value, a tungsten source and a silicon source are added, and heating thermal insulation treatment is carried out so as to obtain a master batch; the slurry and the master batch are uniformly mixed, press filtration is carried out, and obtained filter cake is subjected to calcining, and crushing so as to obtain a finished product. According to the preparation method, raw material quality is controlled, ratio is adjusted, the corresponding preparation technology is adopted, so that the obtained titanium tungsten silicon composite powder isrelatively large in specific surface area, possesses high temperature aging resistance, is wide in catalytic temperature range, is high in nitrogen removal efficiency, low in drying cracking rate, and shedding rate, long in service life, and promising in application prospect.