The deposition of corrosion product Fe₃O₄ on the steam generator heat exchange tubes and supporting tube sheets is one of the main causes of corrosion accidents in the secondary circuit of nuclear power plants. Adding a dispersant can reduce the amount of corrosion product deposition. In this paper, polyacrylic acid (PAA) is selected as the dispersant, and its dispersion effect on Fe₃O₄ was examined in water with different concentration ratios of PAA to Fe₃O₄ (0, 0.01, 0.1, 1, 10) at ambient temperature for 0 and 24 h respectively. Then the effect of PAA on the dispersion characteristics of Fe₃O₄ was assessed via coupon test with a simulated secondary loop operating condition (autoclave), as well as the corresponding oxide scale formed on carbon steel was characterized by means of SEM with EDS. The results show that the addition of PAA will increase the absolute value of the Zeta potential of Fe₃O₄ and reduce the particle size of the corrosion product Fe₃O₄. PAA has a good dispersing effect on Fe₃O₄, when the concentration ratio of PAA to Fe₃O₄ is 0.1, the dispersion effect is the best. When the Fe₃O₄ concentration ratio is too large, the particle size increases and the dispersion effect decreases. With the increase of PAA concentration (0, 10 and 100 mg/L), the deposited Fe₃O₄ particles_{on the steel surfaceafter tested in autoclave are finer so that the oxide scale on carbon steel coupon was much dense and uniform. As the PAA concentration increases, the C content of oxide scale on carbon steel surface increases, indicating that PAA participates in the surface film formation process. The above results can provide certain theoretical guidance for the application of PAA in the secondary circuit of nuclear power plants.}