The invention discloses a stepped utilization method of steam in ammonium phosphate production, which comprises the following steps: 1. three-time steam generated by two-stage concentration is introduced into a heat exchanger to heat and pre-concentrate raw material of thin phosphoric acid, and after heating, the steam at the terminal is discharged and condensed, the temperature of which is lowered; and 2. part reaction heat generated by neutralization of raw material of the phosphoric acid and ammonia is still used for secondarily concentrating ammonium phosphate slurry, and the other part of the steam continues to heat the raw material of the phosphoric acid by single-pass falling film evaporation so as to further pre-concentrate the phosphoric acid. The method has the advantages that: (1) by lowering the vaporization temperature at the terminal to 50DEG C-60DEG C, low-temperature pre-concentration of the phosphoric acid is realized, which saves the consumption of primary steam and reduces the emission of waste heat and gas; (2) auxiliary equipment runs steadily, forced circulation has high evaporation intensity, circulating power consumption is reduced, and the size of the equipment and pipelines is reduced; (3) the operation temperature is obviously reduced, and the corrosion and scaling on a heating surface caused by a concentrated medium are improved; and (4) the concentration operation expands towards a low-temperature area, thus improving the functions of the equipment.