The invention discloses a preparation method of a pressure-resistant sound absorbing brick and belongs to the technical field of building materials. The preparation method comprises: orderly weighing70-80 parts by weight of cement, 15-20 parts by weight of a modification additive, 8-12 parts by weight of a treatment agent, 2-8 parts by weight of reinforcing fibers, 1-5 parts by weight of sodium chloride, 1-5 parts by weight of calcium bicarbonate and 50-60 parts by weight of water, mixing cement and water through a stirrer, orderly adding the modification additive, the treatment agent, the reinforcing fibers, the sodium chloride and the calcium bicarbonate into the stirrer, carrying out mixing at 50-65 DEG C at a rotation rate of 220-300r/min for 45-75 minutes to obtain a cement mixture,pouring the cement mixture into a mold, carrying out vibration molding, carrying out curing at the room temperature for 5-8h, carrying out demolding to obtain a blank, and curing the blank in a dark place at the room temperature for 10-14 days to obtain the pressure-resistant sound absorbing brick. The pressure-resistant sound absorbing brick has excellent compressive strength and good sound absorbing effects at different frequencies.