The corrosion behavior of austenitic stainless steel S31655 in a simulated industrial wet process phosphoric acid solution at 25^oC, 40^oC, 60^oC and 80^oC was investigated by means of electrochemical test and XPS technique. The results show that: with the increasing temperature, the corrosion resistance of S31655 decreases and the is a critical point at 60^oC, while the corrosion resistance decreased significantly at 80^oC, meanwhile, the defects concentration N_D of the formed passivation film increased, its thickness W_sc decreased, and thestability deteriorated, meanwhile, the semi-conductivity of the passivation film transforms from n-type semiconductor to p-type semiconductor by potential above 0.7 V. Results of XPS spectra show that Cr₂O₃and Fe(Ⅲ) etc. could improve the corrosion resistance by stabilizing the passivation film, and ligands $\mathrm{NH}_{4}^{+}$ and NH₃ could inhibit the corrosion process by acting as retardant to acidic solutions. The presence of a critical temperature is associated with an increase in the solubility of N and $\mathrm{NH}_{4}^{+}$ in the passivation film at 80^oC. The increase in temperature simultaneously promotes the generation of soluble Fe(H₂PO₄)₂ and porous films, and the significant enrichment of Ni and N in S31655 leads to a decrease in the precipitation rate of Cr₂O₃, but also promotes the full crystallization and structural stability of Cr₂O₃, thereby improving its corrosion resistance.