The invention relates to a preparation method of a low-deformation antibacterial 
polyurethane automobile shock absorption bumper block. The preparation method comprises the steps of preparing low-deformation antibacterial 
polyol, preparing a 
prepolymer, performing 
casting molding, pre-curing and demolding, and performing 
post curing to obtain the low-deformation antibacterial 
polyurethane automobile shock absorption bumper block. According to the preparation method, as 
polyester polyol of which the number-average molecular weight is 2000+ / -200, 
castor oil which accounts for 0.5-2% of the 
mass of the 
polyester polyol and an 
antibacterial agent which accounts for 0.5-2% of the 
mass of the 
polyester polyol are adopted, and a 
tertiary amine catalyst, water and organo-
siloxane which account for 3+ / -0.5% of the total 
mass are added as raw materials, on the premise that other performances of the 
polyurethane automobile shock absorption bumper block are not influenced, the after-fatigue deformation of the bumper block is reduced, the 
antibacterial property of the bumper block is improved, the phenomena of 
fungus catalytic hydrolysis aging, color deterioration, material fracture, light-
colored product yellowing and the like are avoided, and meanwhile, the problem that part of the antibacterial gent is unstable and easy to hydrolyze is solved, thereby meeting requirements on the 
antibacterial property of the automobile bumper block by middle and high automobile markets.